Six years after Civ 5, I wish this game were more of an improvement. It's nowhere close to the massive step forward from Civ 4 to 5. And while some elements have improved, others feel lacking. I'm glad to see the return of the government system, but it feels underdeveloped, and the ability to simply swap out policy cards with no political blowback feels very out of place. You're ostensibly rewriting the social fabric of your civ, and yet it's just pick and choose. I'd like to see more penalties for switching, and some synergies with certain governments and policies. While I appreciate the faster pace, the maps seem much tighter, with almost no neutral ground left after the first 50 or so turns. The religion mechanic is mostly unchanged, and still feels like an afterthought, with little decision making beyond send-moar-missionaries.
If it weren't for the wonky new graphical scheme, it would be hard to pick Civ 6 apart from a Civ 5 expansion