I would like to add my voice to the chorus of praise; this total war game is the best one so far. To anyone wondering whether to buy it after a poor experience with empire; buy it. Its worth it.
That said, for all the complaints about unnecessary patches, I do hope they release an actual major patch some time soon; there are bugs of all kind scattered throughout the game. Nothing game-breaking, but annoyingly noticeable nonetheless- and hopefully minor enough that they can be fixed easily.
The diplomacy ai is also much better I think. I've only played through 1 campaign so far so it might be too soon to decide, but so far I haven't had any uncalled for back stabs.
I don't know if this is an intended feature, but in my current game, it has happened thrice that a medium-sized clan declared on one of my one-province-vassals (gotta keep that expansion down somehow), whereupon I swiftly handed their asses to them (resulting in yet more territory expansion- dammit). One of the times, it was one of my allies who declared on them, but
I was the one who had to foot the honour penalty for breaking an alliance.
As I said, this might be intended. But it sure is stupid- I think it would be better if the AI regarded vassals as being part of their parent nation, rather than tiny bitesized chunks of fodder.