The game is in a much better state than it was at release, to the point where it's really starting to reach its potential. The thing that I've noticed the most is that the balance is just leagues better than it used to be (thanks in no small part to a bunch of ideas lifted from mods); tall vs wide empires are a meaningful choice, as is warfare vs building, gold vs production vs food, culture is a worthwhile investment for its own sake (not just for a culture victory), most of the buildings are worthwhile, etc etc. It's a bunch of fairly subtle changes that add up to a much much better balance and flow. It's a huge difference. The AI is much improved for the most part; they settle pretty sensibly, improve pretty sensibly and build pretty sensibly. They fight wars as sensibly as could be expected and tend to try and keep fragile troops out of harm's way, while being pretty ruthless at targeting your weak troops. They're capable of quite good "dagger" sneak backstabs with massed combined arms forces when your troops are off elsewhere, which I think is fantastic. The diplomatic AI isn't broken, but I wouldn't say it's better than serviceable. It's sort of at the level you'd probably expect from an initial release; not a highlight, but by no means a game-killer. Primarily, I think it just isn't given enough parameters with which to make judgements, and could use more friendship and enmity modifiers (e.g friendship for trades, a couple of scaled levels for warmonger hate, enmity for razing and nuking etc etc). As far as warmonger hatred for taking cities when you're attacked - of course people are going to get upset if you start taking heaps of cities in a "defensive" war. Civ V is far from alone in this either. EU3 for example (perhaps the game with the most nuanced and complete diplomatic system around) still gives you plenty of badboy infamy if you take a bunch of territory that you don't have a claim to, even if you didn't start the war. Honestly, I think the major problem the game has now is selling luxury resources to the ai for gold, and the zero-sum foreign trade game more generally. Other than that, even the vanilla unmodded game is now really very good.