Diplomacy's pretty good. Just expect the AIs to behave more like human players than a strict historical simulation
This isn't accurate:
- human players won't consider someone on strict defense a warmongering menace
- human players will continuously gun for the top opponent in an effort to win
- human players, for the most part, will not implode into 2 cities for 100's of turns and not try to win the game.
- human players don't struggle with DoF and needing to space those out.
The AI is a little bit more cut-throat than it might have been in the past (if you're not busy taking advantage of it instead), but there's nowhere near a semblance of competent human play there, or even an incompetent human's attempt to win.
It's not nearly as opaque or confusing as some like to pretend, as long as you take time to think about the consequences of your actions.
The XML suggests it's pretty opaque and confusing. I bet the vast majority of people who haven't read that xml material are mistaken about how the game's AI works. Pretty interesting for a game intended for casual gamers.
Trading's improved, too. The last patch fixed a bug where the AIs didn't take spare strategic resources into account when negotiating a luxury trade, for example.
However, it still gives lump sum gold for dubious per turn obligations, creating droves of "exploit" complaints across multiple subforums on what kinds of behavior is acceptable for the human here. The competitive scene is a mess. Whether the competitors themselves or the game is to blame in this instance is debate-able, but AI that allows itself to be badly fooled certainly isn't helping the equation - this kind of thing isn't seen in other "AAA" games to the same extent.
Barbarians have been a trash chance element for multiple iterations of civ - 5 is no exception (other than now they can be used to farm positive luck as well as negative). Getting tele-fragged by a barbarian unit that appears in view from thin air while trying to clear a camp is pretty chancy, but then again people seem to LOVE chancy stuff that doesn't have anything to do with the "s" in TBS, which is why firaxis screwed us with events in civ IV and chose not to balance those. Is skill-dorado any better
?
OP might nevertheless find the game enjoyable, but it is still far from being a finished, reasonably competitive tbs title as long as some of its core elements are questionable.