I just wanted to echo what many other folks on here have said about the general sense of disappointment with the game. I've been playing Civ for a long time (since the original). I love PC strategy games, especially ones with some depth and complexity to them - which had been a characteristic of Civ up until now . . . Let me lay out my likes/dislikes more specifically:
1) Hexgrids - they make movement and tactics much more interesting and they make the map look more realistic
2) Combat - eliminating unit stacking and adding in ranged units and terrain modifiers for range really added depth (and fun) to the game
3) Graphics - especially the unit and combat animations are very well done
1) City States - just my personal opinion but I'm not a fan. Your interactions with them are too limited. You can't even make direct diplomatic deals like alliance except for bribing/completing a quest and waiting for your favor to decay over time
2) Social Policies - these were almost a "good" thing. I do like the variety of options available to customize the bonuses for your civ. But the system is too detached from the rest of the gameplay. At least with gov't types or religion (that got replaced by social policies) it made a huge impact on the diplomatic interactions - other civs would like/dislike you based on your choices and you could try and influence other civs through military or peaceful means. Social policies just seem . . . simpler (kind of a general theme with Civ5)
1) Releasing an unfinished product - I'll forgive many of the annoying bugs. I play alot of PC games - I'm used to this by now. But I'm not willing to forgive an unbalanced AI that makes it nearly impossible to win by pursuing a nonmilitary strategy. Every game I've played has featured one militaristic civ that serially invades all its neigbors leaving the conquered cities as puppets (with apparently few penalties for overexpansion) and can't be prevented from invading you except through a massive military buildup of my own. And all this after hearing about how "advanced" the AI was going to be from the game developers. Poor form.
2) Border growth - the system is too simple, cut and dry, all or nothing. So once I purchase a tile right on the border of another civ, I just own it for good (short of conquering the city or using a great artist)?. There's no impact of the cities relative culture? And once you do conquer a city you just automatically inherit every attached tile? Even if there's tiles of the former owner immediately adjacent? No mechanism for accounting for the fact that the Japanese are now controlling a German city? (except for a few turns of unrest) And if the Germans were to reconquer it they get treated just like any other conqueror? Way too simplistic - far inferior to the culture and nationality system from Civ4
3) General lack of detail - I've read plenty of interviews and developers journals and I know the justifications for removing the religion system AND streamlining the tech tree AND taking out government types. But the replacement systems don't come CLOSE to replacing the choices and depth. Even the civilopedia doesn't list the actual stats and bonuses for most of the units/buildings - it just describes the effects in general terms.
Taking all the different game design elements and changes together, it's readily apparent that the developers were trying to make the game more accessible to gamers unfamiliar with the franchise. It looks more like a console game (similar to Civ: Revolutions). It minimizes or hides many of the details involved in administering your civ by using a slick interface. But in making the game simpler they took out most of what makes me a fan of the Civ series. This game just isn't as fun. And, to be honest, I feel kinda betrayed. The developers made a concious choice and chose to prioritize newcomers to the franchise, console gamers, and people with ADD that can't handle complexity over franchise veterans like myself. There are many people like me that have probably logged hundreds, if not thousands, of very satisfied hours playing Civ games over the years - Civ5 is not worthy of the series.