Gift Culture (from start)
Give gold to other nations in return for culture.
Culture, especially early on, is used for expanding borders to deny access to areas or push against another civ's culture. This makes it highly location specific and is city based. Does the gift target the culture toward the closest city to the gifted country (probably overpowered)? to a chosen city (definitely overpowered - see culture bombs with great leaders)? or just into the civ pool (more or less useless early on)?
Bureaucracy (requires Literacy)
Palace doubles city worker output of your capital instead of culture bonus
I see Bureaucracy as adding central management, which in turn helps focus monetary, cultural or scientific goals. Never really perceived politicians as a steel works.
Vassalage (requires Feudalism)
Plains and grasslands generate +1 trade if they contain your military units
Nice idea, possibly need something extra than just one trade as once you're past the military cap your units would be costing you more than the bonus. Might be a nice balancing act though and definitely gives military nations another avenue between wars.
Capitalism (requires the Corporation)
Double the bonus of resources.
Sounds Ok if it's just trade/food/hammers, but doubling the happiness from resources would be game breaking, allowing a massive population advantage.
Paganism (from start)Barbarians usually only play a part in the first couple of centuries, but it might be a nice decision between that and Ancestor Worship for the fast religion civs. Usually you can't wait getting off the bottom rung civics. That's a nice choice in not giving an advantage for this civic, but removing an option in going to another. Later on in the game it's usually an agonizing decision as to exactly when to swap to another civ. Nice to see some effort in bringing that to the start too.
Barbarians can be friendly
Ancestor Worship (Ceremonial Burial)
Your units being killed generates culture
Nice. Might suffer from the same problem as before of defining what city to attribute the culture to (closest city? home city?). Anyone going the passive-agressive route of culture spread would love this as it would be far cheaper building 2 warriors and imploding them on an enemy than building a monument. Maybe not the actual ancestors you were wanting to venerate .. ;)
Add two new terrain types: jungle, and wetlands
Settlers can convert some terrain types in return for gold. This takes a full turn and requires that the settler has movement still available.
I've tried a couple of mods that allow greater flexibility in deforming the landscape and, although I craved it at the beginning, it destroys the replayability. Every town on every playthrough eventually becomes a mirror of your perfect city. Maybe I'm a sucker for exploration and map design, or I've just played it too much, but the shape and structure of the map is the largest influence on the type of cities and playstyle used for each game, which in turn brings something new each time you restart. (As an aside, make sure you try the tectonics map choice in BtS. Very, very nice)
A big part of the problem is that it is too easy to boom while you're rushing: you steal geographical space over the map which then lets you build anywhere. Starcraft avoids this problem by geographically concentrating the resources required to build expansions in a few discrete areas instead of all over the map.
I didn't really get to see this being addressed in the changes, in fact most changes were about enhancing production that would aid the rushing strategy. To emulate the starcraft analogy would be to play with high corruption so that each city needs to be a valuable choice rather than simply filling in the gaps (although filling across a choke could be valuable enough to do). With more space unclaimed on the map it allows barbarians to work their magic too. Problem with this is that it doesn't feel like you're building a civilization anymore, but playing a strategy game (Most civs would optimise to a semi-hollow circle, rather than having a productive, peaceful, populated core)
Can't believe I'm advocating corruption as it's one of the features that nearly put me off civ4. In earlier civs corruption was nowhere near as prevalent and you could more or less take over 70% of the world (as in CivRev too actually). This feels right when you're in expand / build mode as by that stage you've essentially won. In Civ4 you can only really get to about 40% without serious repurcussions, which is by no means conclusive. Once you get to that stage there's no point retaining conquered cities so the game ends in a massive slash & burn of ~50% of the map. Corruption needs to be more exposed if you're going this route, as well as a serious look into vassalisation (ala crusader kings) to make a slow conquer possible.