Well with ES it's not really that it's stupid (It's not a genius either but), the diplomacy tends to make sense and it explicitly tells you things like "You're growing really stupidly powerful and people are getting scared" and stuff like that, it's just that it's all impersonal and interchangeable. With the sole exception of the Cravers (because their only diplomacy options are War and Cold War) every race is essentially the same to deal with in diplomacy terms, and it's not that it's bad so much as it's a crying shame because some of the race ideas are so damned good.
I can understand not liking unit stacking especially in civs where doomstacks can reign supreme, but the 1UPT system of Civ 5 just doesn't work in my eyes because the game isn't big enough and you end up with the entire world carpeted in units. Not to mention the 1UPT decision influenced everything else in design terms and this has made it a game I just don't like or enjoy one bit
