So we are talking about civics? In all honesty changing them isn't that difficult just some XML editing, well unless you want to get fancy.
Anyway my main problems are:
1) Conquest: this is civic witch ironically doesn't reward conquering, it's just as good for civ that don't cottage and want better units for defence. My proposition here is to reward aggressive players and made it pointless for peacemonger.
->
+100%
when taking a city - this isn't as powerful as it seems conquering new big city is not that common occurrence in classical era.
->
-25% XP needed for unit level up or +100% XP gain for units -> you will be rewarded for combat making it easier to build experienced army.
2) Republic: currently only use of this is for Carthage due to they UP other civs almost immediately should switch to despotism or monarchy. Early there isn't enough

/

or specialist slots for this civic to be useful.
->
+
per specialist - I really liked that effect in some previous versions, with some initial building investment it allowed me to run early specialist economy.
-> can hurry units with

- no change here.
3) Colonialism: My main problem here is +XP for water units it's rarely useful drydocks are usually enough for purpose of navy building. Secondary, costs of colonial empire can balloon really quickly and +

per colony isn't enough to offset it.
->
remove +4Xp for water units add: reduces colonial maintenance - should be enough for building large colonial empire.
4) Multilateralism: Bunch off effects that aren't that well put together, and defensive pacts with AI are rarely good idea. But honestly here I don't have good idea.
Okay then so how about:
- Vassalage: +1 production per Farm
- Central Planning: old school +1 food per Workshop, Watermill
- Ideology: +1 production per Workshop, Lumbermill
- Nationalism: +1 production per Town
This is good but then I will vote for removing vassalage fort and castle bonus, nationalism fort bonus. Just to make it less cluttered.