First impression - quite a bit changed. Lotsa new stuff and lotsa tweaks.
I'm enjoying it so far.
Combat AI is a little better so far. Decent use of generals and guarding them. Attempts at withdrawing damaged units. Range attacks before melee. Focused fire.
I'm more of a builder but ended up tyring Attila since the battering ram looked interesting (and seems insane - I'd imagine pro warmongers will love it). Horse archers are pretty nice too.
Could you tell us, how the social policies changed?
In liberty republic (production) and collective rule (settlers) swapped places.
Completing tradition now also gives free aquaducts in your first 4 cities (I think this is new).
Piety got some tweaks for faith, including organized religion giving a faith bonus instead of happy.
Commerce got a few tweaks - haven't tried it but it looks a bit more interesting. Completing also allow buying great merch for faith. I haven't done commerce in ages so I'm not sure if protectionism changed (+2 happy per lux - seems powerful enough that I would remember but who knows).
Completing order lets you buy great engineers for faith. Not sure if anything else was tweaked.
Completing autocracy enables purchase of GGs and admirals for faith. Probably some other minor tweaks.
Freedom - artists for faith;
Rationalishm - scientists for faith - which is somewhat amusing
Can someone tell me the state of Songhai's ability as well as the status of the buildings that replaced Temples (Mud Temple Mosque and Burial Tomb)? Thanks
Mud pyramid mosque gives 2 culture and 2 faith for no upkeep. Askia is still 3x pillage/plunder and land units get promotions to make them stronger when embarked.
Burial tomb gives 2 gold and 2 failth with the same capture penalty.