Buildings:
- Market (but lower the inflation/upkeep rate so your economy doesn't automatically go to hell after you get like 3-4 cities)
- Elder Council
- Pagan Temple
- Herbalist
Actually I like all of those. They provide strong bonuses at the beginning of the game, and give early specialists. They should stay.
Get rid of building pre-requisites for units altogether. They are just an annoyance and hinder the AI. So remove/change the following:
- Hunting Lodge (or just have it provide XP)
- Mage Guild (or just have it provide XP)
- Archery Range (or just have it provide XP)
- Bowyer
- Stables (or just have it provide XP)
- Hippodrome
- Large Animal Stables
- Weaponsmith
- Training Yard (or just have it provide XP)
- Siege Workshop (or just have it provide XP)
- Machinists Shop
- Bear Totem
I like those, and besides, thats half the buildings in the game!
There is something to be said over building pre-reqs crippling the AI, but I think that changing the buildings to grant xp is not a good idea, at least not for all buildings (there is probably enough xp out there from other sources already). Perhaps its best to simply make the "no AI building requirements" option be enabled by default (I always turn it on at any rate).
Machinist Shop, Bowyer and Hippodrome are already decently useful, but the latter two could use some beefing up. Bear Totem and Weaponsmith can probably be removed though (they arrive late and provide no meaningful benefit). Alternatively, the team could make those buildings useful:
- Weaponsmith: increase the unit production bonus to say 20-25% and give it some sort of economy malus (say some
)
- Bear Totem: make it a Doviello UB, grants melee units the Savagery promotion (+1 offensive strength, +10% city attack). It would help to give the civ a little more flavor near the end game.
Wonders:
- Mokka's Cauldron
- Catacomb Librarus
- Temple of Temperance (or give it a more interesting bonus)
- Hall of Kings (or give it a more interesting bonus since it is similar to theater of dreams)
The first three are cool IMO. Although, now that the graft flesh spell is gone, it might be a decent idea to change Mokka Cauldron so that instead of its current effect, it allows living units in the city to be turned into Flesh Golems as per the current spell. It would be a big buff to the Cauldron.
Good point about the Hall of Kings though. Might be a decent idea to change it so it works like the Sistine Chappel in BTS (+2 culture per specialist, and +5 culture per religious building). Maybe even remove the bonus to specialists and make it a plain +5

bonus to state religion temples and shrines (maybe include basilicas, asylums and the like too).
Units:
- Lightbringers
- Trojan Horse
- Dragonship (or cut any one of the dragon/trieme/galley trio)
- Crossbows
- Berzerker
Techs:
- Tracking
- Rage
Promotions:
- Scourge (for the same reason elf/dwarf slaying was removed)
- Demon Slaying (for the same reason elf/dwarf slaying was removed)
- Undead Slaying (for the same reason elf/dwarf slaying was removed)
- Mobility (I agree with what the others have said about mobility. Get rid of mobility II altogether and make mobility I only available to mounted units (and disciple units for spiritual civs)
Game Mechanics:
- Terraforming. I'm sure I'll be roasted on a spit for suggesting it, but it is tedious micro-management and the AI struggles with it. I know there are many players who love crafting perfect cities and want every bell & whistle imaginable, but I think it hurts game play. It takes away strategic choice. Instead of making a difficult choice over where to place cities it doesn't matter anymore. Any spot on the map will, eventually, become a paradise. Terraforming is so powerful there is just no decision, everyone will do it. I recommend keeping bloom for druids, maybe keeping Genesis, but getting rid of scorch, spring, and vitalize. I think it would be very good for the game. I know it'll never happen, but cutting terraforming is my strongest recommendation.
I don agree with any of those (except removing tracking). Interesting reasoning on terraforming though.
That said, it might be a good idea to make terraforming more difficult. In particular, maybe Summon Treant and Vitalize should switch places so that Vitalize becomes a FoL-only spell and Nature III Archmages gain a summon.
That would help to restrict terraforming somewhat, making it available only to FoL players (and non-dwarven neutrals via Druids).