After a good 24 hrs spent playing Civ V here's my 2 cents...
The Good:
Hex tiles and 1unit/tile. Combat has more depth than simply making a stack of death and ransacking cities. Also the combat seems to be well balanced. I also like the road revisions, road maintenance makes sense and cuts down on sprawl. The lack of tech/gold sliders is an improvement in my opinion. It always felt rather artificial to set the research rate like a god.
The Bad:
The AI is lacking. It shows little sense in combat at all, and even less in diplomacy. The worst is in resource trading. When I try to obtain a luxury resource from an AI civ, they will accept no less than 4 lux. resources of my own as a "fair trade." Also, they'll give me jack for my resources. As has been mentioned many times, unit and building times are totally whacked, but this can be fixed rather easily. The UI is slightly irritating, but not completely incomprehensible. Two other major issues I have are:
1) strategic resource consumption: resources like Iron, Uranium, and Oil are consumed when you build a unit/building that requires them. The upshot of this is that your armies and buildings are limited by the number of strategic resources you have. I understand that this is to make resources more important, but it becomes completely nonsensical in the industrial and modern eras. For example, in my American game playing on the largest map size I own ~half the largest continent (out of 3) but only have 2 uranium sites, with 3 more easily obtainable. This means that I can have at most 5 nuclear missiles at one time. So much for my plans to wipe those annoying arabs off the face of the earth
Oil is similar, limiting the number of aircraft, boats and tanks I can field to ~25. Totally unrealistic.
2) There is no foreign trade: In all honesty I think they should have left the civ4 trade system. The only trade routes in the game are between your cities and your capital.
So, for ROM in civ V I'd suggest (in no particular order):
-revolutions and individual city happiness
-emergent factions: It would be awesome if city states could become empires in a system similar to the minor civs in ROM
-Faster Culture spread around cities (it takes forever!)
-more techs/units/buildings/wonders and faster build times
-religions would be nice
-civics would also be nice; perhaps the social policies could enhance civics?
-Improved AI in diplomacy and war
-Future eras with hoverships, maglevs, and thermobaric tanks
-more resources and improvememts
-Bigger map sizes and longer game speeds
-MORE CIVILIZATIONS
-usable mountains
whew!
