My father, who is 75 and plays Civilization V quite a bit, called me up after having played Civ VI some this morning. His very first comment was to complain about the graphic style. "I don't think it's a step forward," he said.
I'm so used to the way the game looks now that I had to think back to my original reaction to the first screenshots, which was essentially the same. I think the graphics are clear and functional, but garish and unattractive. And it's not just the civ fanatics who think so.
Since I'm used to the look, it doesn't bother me anymore, but having played the game for the first time I'm disappointed in the flow and usability of the UI. There are lot of hiccups and unnecessary extra clicks and lots of waiting for no good reason (especially in the diplomacy screens). I'm very surprised that it's so clunky.
I thought the map elements is essentially what Civ4 would look like if it was made with 2015-2016 graphical tech, it had more colour than 5 and a lot of whimsy to it.
My biggest gripe is the in-game art; literally the pop-up artwork that look like they belong in an iPad game. Just not for me. But the actual graphics is really nice. The fidelity of the graphics are astounding.
My biggest gripe is the as with you, the UI. I expect menus and clickies to be in the middle of the screen, but I often find them tucked away in the corners and edges of screens (Wonder screens has this really weird overlay where when the animation finishes, you'd expect to hit any button to exit and back to your game, instead of clicking an 'x' hidden to the side)
I also constantly move units I didn't intend to because the previous unit ran out of Movement points and the game immediately hands me off to the next unit without enough of a lag/visual cue to confirm that it is switching to the next units. So I'd be doing my thing and five turns later, I notice my builder is on his way going to an island... because I was clicking on a tile on that island with my scout 5 turns earlier...