Oops missed people had responded to this for the past few days.
Two kind of general notes before I give some scattered responses to the particular civs:
1) I think it's worth reiterating that it's not that these civs are unplayable or even have nothing going for them (some are kind cool), but that there is very clearly a good bit of space between these civs and the top tier of civs in quality such that there's room for improvement. This might make the whole point nitpicky, but then this is a hobby and I find this discussion fun. And in some of the cases I think the civ def needs buffs, ex: japan.
2) Not enough time to directly respond to everyone (thanks for the responses by the way), but will try to implicitly hit all the points in each civ's discussion. Relatedly, going to tend not to talk about what the actual fixes should be most of the time, but that is purely a time issue on my part and is obviously important.
Germany
The obvious problem is that everything comes too late, and so has comparatively smaller impact on the game. I don't think coming late itself is a death knell, but it means I think the actual bonuses need to be somewhat larger. I actually like the flavor of germany becoming super cool right as the industrial age hits, just think the bonus should be larger if we're keeping it's stuff all so late. It has roughly ancient era "boosts" to UU/UB, but coming at a time where having such a boost is a comparatively small boost to your overall strength (and obviously snowballs less).
I agree (GJ had good description) that Kanone are probably good as they are, and cheapness is a cool "special" for a UU to have (especially a collateral UU). Really it's the UB that feels like a very minor boost.
Maya
Considering this more, I think the problem with Maya is a magnified version of the problem I think still exists with Cha to some degree. Our map design tends to generally give plenty of happy resources which obviates how helpful happy-boosting abiliites are. This is way worse for the Ball Court than Cha though, because the Ball Court requires investment AND because construction comes about the same time you get access to all the calandar resources and get to stop caring about happy for a long while.
It may only be a sample size of 5, but I haven't had a game yet where after calendar I felt myself really at all pushing the happy cap. By the time I went past luxuries + markets-in-top-few-cities-or-so I had HR and enough military units lying around to easily manage happiness in every city, though I still only needed 1 garrison unit in the vast majority and really just needed military to manage transitions. Or put another way, if you gave me access to Ball Courts in all of those games I still probably would have built none of them until the era of drafting.
I don't think this is purely a cre issue, it's an issue of the that bonus being provided by the building is often just not needed. If I was Cre + had Ball Courts I probably would build a few just because of how cheap they were, but even then it wouldn't be THAT much easier to manage happiness, because it really just wasn't hard at all before. And I think having a UB REQUIRE a trait to be worth building is subpar design. I don't think the list of Exp UU's are ones I'd never build without Exp, and even the university UU's will get build without their trait if only for OU.
Holkans are pretty cool. I don't think Maya sucks. But I think it shouldn't have a UB that in many many games I would just literally never consider building.
re:unique start techs - is Mining/Myst a desired option? They may be the only one but this seems like a starting tech combo that would be subpar in the vast majority of starts. The only scenerio I'm really thinking of this would be desirable is if you wanted to go food tech -> religion -> bronze working, but then it's just identical to starting with food-tech/myst anyway and going mining->religion->bronze working. And in that latter case you'd probably want to actually go religion->mining->bronze working most of the time, making food/myst the better option.
Not saying we necessarily need to fix the start techs, just that them having unique start techs isn't really helpful if the start techs aren't actually good.
Sidenote: I actually really want to play CHA in a RtR game. I probably value the happy bonus lower than a lot of people, but I the promo bonus is really good. Longer game times + west-point buff + SoZ + vassalage buff make the promo game a ton more interesting compared to base BTS. In particular, either Cha or Agg is pretty much required for mass produced commandos...
Korea
Eh, I think H'wacha's are accurately cast as meh. The general power of mounted units means they usually won't get their bonus (or even cause a switch in the top defender), and given they are seige the point of what they do isn't particularly tied to the unit they directly attack. You care more about hte collateral, there will probably be mounted units to take the top hit anyway, and even if you did manage to fight a melee unit you can't kill it while attacking.
It seems most relevant actually for making hwatcha's amusingly good stack defenders AGAINST melee units, but how often does that actually come up? They still don't make good city defenders b/c no defense bonuses (making them not a great counter to the newly improved swords), so we're really talking about defending an attacking stack or something from... a bunch of melee units coming to kill it? In the era of stack-on-stack warfare does that actually happen? It seems they help not at all at defending from the standard tactic of hit with collateral then use horses to flank away enemy collateral.
UB i think is less complicatedly just obviously "ok" at best but mostly meh, hampered by the problem that universities just really aren't good for non-Phi civs. I think it's a bit worse than the research institute, which gets extra points in my book for being doubly-synergistic with Phi, which is the only scenario you'd build a ton of them in anyway. More importantly the research institute is attached to Russia, and Cossacks I think are actually solid, as opposed to the Hwatchas.
Fixing this is obviously impacted a lot by any changes to Universities / Oxford, though I find the idea of making Oxford easier to unlock a pretty interesting boost for a UU (though wouldn't the code change actually be for OU?).
Greece
I think i've been convinced Greece is better than I thought.
Japan
That UB seems potentially very cool, but is obviously a large change so I'd have to think more on it. Though I kind of want the Samurai to be something worth building a lot of for purely personal flavor reasons, which is hard given they're a UU to a pretty meh base unit. I liked the 2 move mace idea, though it is probably OP to have 2-movers with access to city raider.
Ethiopia
Krill's proposed fix I actually really like. I think that would put it solidly in the "very good" category, with the bonus of enabling a cool early strategy // being interesting.
Spain
It is possibly that my feelings towards Conquistadors are being biased by weirdly short lifetimes for Cuirs in the games I've played (ex: could build them for maybe 5 turns in PB18, whereas I believe you still have them 20 turns or something after unlock?) But granting that I still think a UB that a majority of the time will be obsolete before it is unlocked is worth fixing. If economics becomes a non-obvious beeline in pretty much all situations, then I think Spain is fine.
America
I like the idea of a barracks replacement for america, agree a good one is enough of a change. Flavor wise I think the two clear choices for America are focusing on the whole "frontier"/colonial america ideal, or alternatively on america's modern economic/military dominance. Base BTS obviously picked the latter, but given the rarity of the true modern era I broadly agree with RtR's decision to move america's boosts to the former.
Two kind of general notes before I give some scattered responses to the particular civs:
1) I think it's worth reiterating that it's not that these civs are unplayable or even have nothing going for them (some are kind cool), but that there is very clearly a good bit of space between these civs and the top tier of civs in quality such that there's room for improvement. This might make the whole point nitpicky, but then this is a hobby and I find this discussion fun. And in some of the cases I think the civ def needs buffs, ex: japan.
2) Not enough time to directly respond to everyone (thanks for the responses by the way), but will try to implicitly hit all the points in each civ's discussion. Relatedly, going to tend not to talk about what the actual fixes should be most of the time, but that is purely a time issue on my part and is obviously important.
Germany
The obvious problem is that everything comes too late, and so has comparatively smaller impact on the game. I don't think coming late itself is a death knell, but it means I think the actual bonuses need to be somewhat larger. I actually like the flavor of germany becoming super cool right as the industrial age hits, just think the bonus should be larger if we're keeping it's stuff all so late. It has roughly ancient era "boosts" to UU/UB, but coming at a time where having such a boost is a comparatively small boost to your overall strength (and obviously snowballs less).
I agree (GJ had good description) that Kanone are probably good as they are, and cheapness is a cool "special" for a UU to have (especially a collateral UU). Really it's the UB that feels like a very minor boost.
Maya
Considering this more, I think the problem with Maya is a magnified version of the problem I think still exists with Cha to some degree. Our map design tends to generally give plenty of happy resources which obviates how helpful happy-boosting abiliites are. This is way worse for the Ball Court than Cha though, because the Ball Court requires investment AND because construction comes about the same time you get access to all the calandar resources and get to stop caring about happy for a long while.
It may only be a sample size of 5, but I haven't had a game yet where after calendar I felt myself really at all pushing the happy cap. By the time I went past luxuries + markets-in-top-few-cities-or-so I had HR and enough military units lying around to easily manage happiness in every city, though I still only needed 1 garrison unit in the vast majority and really just needed military to manage transitions. Or put another way, if you gave me access to Ball Courts in all of those games I still probably would have built none of them until the era of drafting.
I don't think this is purely a cre issue, it's an issue of the that bonus being provided by the building is often just not needed. If I was Cre + had Ball Courts I probably would build a few just because of how cheap they were, but even then it wouldn't be THAT much easier to manage happiness, because it really just wasn't hard at all before. And I think having a UB REQUIRE a trait to be worth building is subpar design. I don't think the list of Exp UU's are ones I'd never build without Exp, and even the university UU's will get build without their trait if only for OU.
Holkans are pretty cool. I don't think Maya sucks. But I think it shouldn't have a UB that in many many games I would just literally never consider building.
re:unique start techs - is Mining/Myst a desired option? They may be the only one but this seems like a starting tech combo that would be subpar in the vast majority of starts. The only scenerio I'm really thinking of this would be desirable is if you wanted to go food tech -> religion -> bronze working, but then it's just identical to starting with food-tech/myst anyway and going mining->religion->bronze working. And in that latter case you'd probably want to actually go religion->mining->bronze working most of the time, making food/myst the better option.
Not saying we necessarily need to fix the start techs, just that them having unique start techs isn't really helpful if the start techs aren't actually good.
Sidenote: I actually really want to play CHA in a RtR game. I probably value the happy bonus lower than a lot of people, but I the promo bonus is really good. Longer game times + west-point buff + SoZ + vassalage buff make the promo game a ton more interesting compared to base BTS. In particular, either Cha or Agg is pretty much required for mass produced commandos...
Korea
Eh, I think H'wacha's are accurately cast as meh. The general power of mounted units means they usually won't get their bonus (or even cause a switch in the top defender), and given they are seige the point of what they do isn't particularly tied to the unit they directly attack. You care more about hte collateral, there will probably be mounted units to take the top hit anyway, and even if you did manage to fight a melee unit you can't kill it while attacking.
It seems most relevant actually for making hwatcha's amusingly good stack defenders AGAINST melee units, but how often does that actually come up? They still don't make good city defenders b/c no defense bonuses (making them not a great counter to the newly improved swords), so we're really talking about defending an attacking stack or something from... a bunch of melee units coming to kill it? In the era of stack-on-stack warfare does that actually happen? It seems they help not at all at defending from the standard tactic of hit with collateral then use horses to flank away enemy collateral.
UB i think is less complicatedly just obviously "ok" at best but mostly meh, hampered by the problem that universities just really aren't good for non-Phi civs. I think it's a bit worse than the research institute, which gets extra points in my book for being doubly-synergistic with Phi, which is the only scenario you'd build a ton of them in anyway. More importantly the research institute is attached to Russia, and Cossacks I think are actually solid, as opposed to the Hwatchas.
Fixing this is obviously impacted a lot by any changes to Universities / Oxford, though I find the idea of making Oxford easier to unlock a pretty interesting boost for a UU (though wouldn't the code change actually be for OU?).
Greece
I think i've been convinced Greece is better than I thought.
Japan
That UB seems potentially very cool, but is obviously a large change so I'd have to think more on it. Though I kind of want the Samurai to be something worth building a lot of for purely personal flavor reasons, which is hard given they're a UU to a pretty meh base unit. I liked the 2 move mace idea, though it is probably OP to have 2-movers with access to city raider.
Ethiopia
Krill's proposed fix I actually really like. I think that would put it solidly in the "very good" category, with the bonus of enabling a cool early strategy // being interesting.
Spain
It is possibly that my feelings towards Conquistadors are being biased by weirdly short lifetimes for Cuirs in the games I've played (ex: could build them for maybe 5 turns in PB18, whereas I believe you still have them 20 turns or something after unlock?) But granting that I still think a UB that a majority of the time will be obsolete before it is unlocked is worth fixing. If economics becomes a non-obvious beeline in pretty much all situations, then I think Spain is fine.
America
I like the idea of a barracks replacement for america, agree a good one is enough of a change. Flavor wise I think the two clear choices for America are focusing on the whole "frontier"/colonial america ideal, or alternatively on america's modern economic/military dominance. Base BTS obviously picked the latter, but given the rarity of the true modern era I broadly agree with RtR's decision to move america's boosts to the former.
Fear cuts deeper than swords.