Another note here: overland speed, and building stacks prior to (or regardless of) garrison requirements would be the ideal things to implement for higher difficulties. I would suggest the current AI should be the basis for hard, and extreme and impossible could be given this type of improvement instead of extra resource boosts.
Current game:
4 life, 2 death, 1 chaos, warlord, alchemy, omniscient, astrologer; barbarian. (I've also found: 1 sorcery book, 1 death book, and specialist.)
Impossible, 4 opponents, Huge land size, Max power, Poor minerals, Fair climate.
November 1409:
I control 2 barbarian cities, 17 nomad cities, 2 lizardman cities. I have 2 amplifying towers. I have 2 myrran nodes, and 11 arcanus nodes.
I've just completed casting Crusade, so I have the highest army strength (I was third before I cast it.) I control 1 tower.
I have 127 combat casting skill (3rd highest), 184 overland casting skill. I have 950 power production (2nd highest).
My opponents (all of whom have alliances with 2 other AI, and no treaty with any other player) in order from weakest to strongest:
Horus:
6 sorcery, 6 life, alchemy, sagemaster. Aggressive Theurgist; nomad.
8 Nomad cites, 1 klackon city. No nodes. Aether Binding.
Has perhaps 15-20% of my army strength (and is the only wizard to have banished any other wizard :P) weakest by far.
Has approximately 150 overland casting skill (highest), and 500 power production (4th).
Lo Pan:
6 Sorcery, 5 chaos, alchemy, rune master. Peaceful Theurgist; lizardman.
4 Lizardman cities, 1 nomad, 5 high men. 1 node. Aether Binding. (He has EVERY disjunction modifier. I am so glad he's peaceful.)
Has roughly 35% of my army strength (4th).
Has approximately 145 overland casting skill (2nd), and 850 power production (3rd).
Tlaloc:
4 Nature, 3 life, 6 death, alchemy (all 4 of the arcanus wizards have alchemy!). Maniacal Theurgist (and all theurgists!); barbarian.
7 Barbarian cities, 2 gnoll. Probably has cities on Myrror that I haven't found (astral gates and controls a tower.) At least 1 dark elf city. One arcanus node. Might have myrror nodes too, but I doubt it due to his power production. Was banished once by Horus and took 17 turns to return; in the meantime he took back his home city, and conquered 2 others.
Has about 75% of my army strength (3rd).
Has around 105 overland casting skill (last), and 250 power production (last).
Oberic:
6 Nature, 4 Chaos, Myrran, Tactician, Sage Master. Peaceful Militarist; draconian.
I only know of 20 cities: 13 draconian and 5 dark elves, 1 dwarf, 1 troll. I only know of 1 myrran node. I assume he has quite a few more cities (probably ~25) and at least 2 more nodes.
Has Doom Mastery and Survival Instinct cast; this has him at 90% of my army strength.
Has maybe 123 overland casting skill (4th) and 1150+ power production (highest).
Playing a completely peaceful impossible game is ... interesting. I'm kind of expecting my first war to be VERY rough. But I can probably wipe out any arcanus wizard in 2 turns. So I can probably turn it from a 4v1 into a 1v1 fairly easily. Will probably lose... 6+ cities, and at least as many node garrisons doing it though. Then it comes down to - can the ridiculously huge amount of dispel power wipe out my good spells, and spell blast lock me down before I conquer all of arcanus. Then, can I hold Oberic on Myrror, or will his huge armies break through somewhere? My bezerkers can dominate him, but my army strength is hyper focused on a few stacks; I can't even try to guard the 2 open towers right now if I get into any wars, so I'm expecting it to be very messy.
The resource bonuses of the AI are crazy. Astrologer Omniscient with 13 nodes, and barely holding onto second highest power production - and none of the AI have power increasing retorts. I'm also sitting on only 4000 gold + mana, whereas my opponents are at 10k, 11k, 30k (!!! this is Tlaloc the barbarian who was banished!), and 16k (and 3 of them have alchemy just like I do!).
This may not be of interest as it is an EXP9D game and there is now EXP9E...
6 life, 2 sorcery, warlord, alchemy, tactician; nomad (I've found no retorts nor books)
Impossible, 4 opponents, fair land size, fair power, fair minerals, fair climate.
November 1409:
I control 1 nomad capital city, 8 lizard cities, 2 hi men cities, 2 hi elf cities, 1 gnoll city, 1 dwarve city, 1 halfling city. I have 2 amplifying towers. I have 0 myrran nodes, and 1 arcanus node. All towers intact.
My capital has been making 1 elite horsebowmen per turn since early in the game. My army strength is barely highest on Arcanus but the Myrran AI is far ahead in all categories. 64 combat casting skill, 78 overland. Power 186 per turn.
I have not played a Caster game much beyond this point, so do not know if I can whittle down the Myrran Merlin and his iron skin stone giants. I have an astral gate cast, have prayer and will have invulnerability in 12 turns to go with the beginnings of paladins and elven lords. I am skeptical of the prospects, but aura of majesty might help, and haven't tried using spell blast yet.
You're on impossible and you have 16 cities in 1409? I'd love to hear more details of how the first 9 years went. My guess is lots horsebowman abuse, crushing as many things as you can. Have you banished/defeated any wizards yet?
started the game sharing a continent with both ariel and freya the lizard so have just razed or conquered as many cities everywhere possible using horsebowmen riding around on floating islands. significant garrisons are required for captured cities with multiple horsebowmen, which can barely keep them in some instances by running outside of city walls. lost one city to a stack but captured it next turn after they moved on. haven't ventured into any enemy capitals as horsebowmen sometimes end up running out of ammo in which case they would be wiped out by lightning. troop shortage all game because of the garrisons needed but all cities well developed. conquered several nodes but have slowly lost them back for now.
I have 9 cities by December 1403, three of them I took from a nearby AI at size 1. Strategy: Gnolls with Omni + Cult Leader + Spellweaver. 4x Life, 2x Death, 1x Nature, 1x Chaos.
Wraithform on Wolf Riders is amazing early game. Sprites counter them, otherwise nothing else can stand in their way. You're all but guaranteed a handful of neutral cities at minimal cost.
I wish I'd taken Warlord instead of Spellweaver, though. Or maybe instead of 2x Life, starting with only Heavenly Light and Wraithform. Those two spells would be plenty to dump my mana on for the first two years.
I take 4 life because I like to have very rates later on. If you're going for a super fast game, you could go less; but I prefer endurance. I don't Sven bother with heavenly light. Its only important until you get your first node, which I usually get in 1402.
8 Death, 1 Nature (Myrran, Tactician, Guardian) wizard. No towers are broken yet, he does not have shadow demons, I have no ability to travel planes.
I just met him; he is at war with one of the Arcanus wizards (all 3 arcanus wizards have astral gate); one of the Arcanus wizards cast planar travel on a Beastman Spearman (why????); the death wizard killed the spearmen in strategic combat, brought him back to life, and then travelled to Arcanus.
It's awesome!
Also, this Myrran wizard has the worst power production (on impossible) of any of the 5 wizards. This seems.. odd.
Warlord, Alchemy, Omniscient, Astrologer
2x Life (Holy Weapon)
1x Death
2x Chaos (Flame Blade)
2x Nature (Water Walking)
This is essentially the sprite strategy on steroids. Speed 5 is often better than Flying in combat, they get to their targets on the map faster, they do more damage and can absorb more damage. There are very few enemies where you'd prefer sprites:
Great Wyrms (won't appear without escorts anymore)
Unicorns (not a big threat)
Wolf Riders (these can be tough without sprites)
In all other cases horsebowmen are at least as good, usually much better. Horsebowmen are also much better node guards. Unbuffed they do about the same damage as sprites, with the potential to gain levels.
It is perfectly feasible to rush an enemy capital by 1403:
Sprites, ghouls, nagas and hell hounds all fall to an equal number of veteran horsebowmen with magic weapons. And with a little luck, city walls won't be up by 1403. Any normal units present shouldn't pose a challenge either. Ideally you'll take out the wizard with 4 expansions planted, you can then milk them for spells as soon as they return.
While wrapping up the first wizard, get ready to do outpost harassment of another wizard. Raze all small expansions that are easy and strike all outposts immediately as they go up. If the wizard is expanding overseas, capture those instead.
In the meantime, make sure to locate a good site for troop production. Mass expansion is not important, but getting an early site with production, coal, mithril, pop 12 or better is crucial. With that out of the way, regular expansion can be delayed a little.