Whining about this and that of a game is, somehow, we gamers' general habitual behaviour, don't you?
Back to OP's original concern, what I say is, looking forward to the geographic factors and the day/night transitions are two major reasons I will consider CIV 6.
I have CIV IV and CIV V, but because of busying at work, I haven't really got the time to play them thoroughly and dedicatedly. But as luck could have it, I am now less busy, so in the last few months I have played numerous number of hours of CIV 5. And I love the game, though there are glitches in the AI even at KING difficulties. But then AI is never perfect.
Having said that, gaming experience is never unilateral. That's many many other things which all come together to give you a feeling of climax. CIV V does that. I didn't spend a great deal of time in CIV IV, because of CIV 5, so I can compare. But just from all the sources online mainly, CIV VI is going to be a blast.
I can wait for a few years until all the expansions come out and get the game just like I did to CIV V, and meanwhile play other titles, but I won't tell you here. If I like it, i ll share it on facebook.