What's so great about Expansive?

[Catwalk]

As the title says, what's the big deal? I see it listed as a high priority pick in most game reports (especially with Financial banned), seems like Creative + Expansive are the two most popular traits after Financial. I'm playing it now, and I'm underwhelmed. With food often contributing around half your production for workers, you get a paltry 10-15% production bonus for your workers. Is it more about +2 health (takes a while to pay off) or double speed Granary (very nice, but they're already cheap) + Harbour (seems less important). I don't see the big advantage here.

How do you generally rate Expansive when comparing with other traits? Assume a variety of game setups, I know that a lot depends on the setup. I'd rate them something like the following:
TOP TIER
1) Financial (major economic advantage, although it takes a while to get going)
2) Spiritual (if you're going to bother switching back and forth a lot for full advantage)
MEDIUM TIER
3) Philosophical (there are relatively few sources of GPs, doubling GP production seems huge to me)
4) Creative (cheap libraries are really nice, main ability is good but can be offset by good planning)
5) Expansive (not bad at all, I'm just underwhelmed)
BOTTOM TIER
6) Industrious (rather nice if there's no stone/marble access, otherwise unimpressive)
7) Charismatic (nice advantages, but kind of small on closer inspection)
8) Organized (money is always good, but seems like the savings are usually minor)
9) Aggressive (sounds quite appealing to me, 10% is no small bonus)
10) Imperialistic (spamming settlers rarely does you much good, GP bonus is good)
USELESS
11) Protective (not useful at all)

[Kuro]

Double speed Granaries make whips VERY efficient and the Worker boost is huge early on, as getting 4 hammers to five can shave 3T or so off of the first Worker, which snowballs into more stuff.

[Jkaen]

The thing is its about snowball effect, so a bonus now is worth far more than a bonus later on.

Plus - how many cities will you build a granary in, and how early in that cities life (when hammers are still rare) will you build it?

Also - Less experienced players tend not to build as many workers, but even so given worker first is the norm here, you are almost starting your game a turn or 2 later than the other player if you dont go with expansive, the snow ball can be tricky to catch up with

[Catwalk]

Would you say the granary bonus is of the same value as the worker bonus?

[Cyneheard]

I think the granaries are a little better than the worker bonus.

Cheap granaries make it possible to get those new cities going that much sooner: that's one extra pop not whipped or one extra forest not chopped, which means that the new city gets moving 5-10t sooner. And the cheap worker usually means your first worker gets going 2t sooner, so your first city is built 2-3t sooner as well. Snowball. I'd say that the cheap granaries are comparable to, say, Creative before it got cheap libraries. Especially if you have another culture source besides 30h monuments (Henge, Missionaries from an established civ, etc. etc.).

An example of Exp being great early: In PBEM4 Vets, I used Exp early to accelerate my civ very well, while using Philo + Egypt's Obelisks to make a quick Theo/Bureau run that ended up paying great dividends. I'd out-expanded other players while spawning 2 Great Prophets and building the Oracle: Exp is that much of a boost.

Then I screwed up around T70-90 or so, and slowed down my expansion in a way that eventually cost me the game to Krill (if Krill had had my set-up on T70 instead of his, the game would've been over 50t sooner. Easily. I didn't grasp the metagame of AW very well, especially once we lost the demographics screen). But that wasn't Exp's fault. That was mine.

Other thing you're missing:

Expansive makes worker whips significantly more efficient, as then the worker is almost completely built with hammers that get the 25% bonus.

[novice]

Yes, when you're expansive you use chops and whips to build workers, and use food surplus to build settlers. If you're imperialistic you do the opposite.

And cheap granaries are often the difference between chopping (or slowbuilding) the granary before the city reaches half a food box at size 1, versus growing to size 2 and whipping the granary with the aid of one chop. You gain 5-10 turns of development in every city. Now it can be argued you should never whip granaries and always chop them, but Expansive makes this that much easier to achieve.

[sunrise089]

Looking at EXP only as half-price workers is about like looking at CRE as free culture or IND as faster wonders

Half-price buildings of the thing you want first and most in almost any city is huge.

[Catwalk]

That's true, I hadn't really taken whipping and chopping into consideration. I suppose that pushes the effective worker bonus closer to 20%. Is there anything notable about getting the granary before the food box is half full? I'd assume there's no difference as long as you get it before growing to size 2.

[novice]

That's true, I hadn't really taken whipping and chopping into consideration. I suppose that pushes the effective worker bonus closer to 20%. Is there anything notable about getting the granary before the food box is half full? I'd assume there's no difference as long as you get it before growing to size 2.

That's how it worked in civ3. In civ4, every food you gain in a city is put into the granary, until the granary contains half the capacity of the food box. This food is then recovered when the city grows. The upshot is that you generally get full use of the granary as long as you complete it before the food box is half full.

[Krill]

On low difficulty/ plus lots of land there is a reason Joao is awesome.

As to a tier list, I'd not bother ranking them other than Exp/Cre/Fin as the top three, the rest depend too much on game and map settings, and Agg then Pro at the bottom. For instance I'd much rather take Org on an archi map than Phi (though I'm starting to come to the conclusion that Phi is junk anyway, and I truly loathe Org).