I'm sure player criticisms of Civ6 and ideas for the future have been taken into consideration when developing Civ7--just like Tamar of Georgia, probably Seondeok of Korea, Lady Six Sky of Maya, and the barbarian clans mode were all inspired by fan input--but I think it's fair to say that any influence fan input has had on Civ7 has already been taken into account: the game has probably been in development for a couple years at this point and one would hope they have a plan for where they're taking it. Crossing my fingers that they ignore all the art style whiners and don't go for a "darker and edgier" style...(I do hope they pick a different style and stick with it consistently, though.)
Having assumed that Civ VII development started when
Humankind was announced, if not before, you will notice looking back that that's about when I started posting about "Perfect 4X Historical Games" and Post-Civ VI possibilities. Here's hoping they've been reading . . .
Now, as for terrain, I completely agree that trying to copy
Humankind is NOT the way to go. Biggest reason is that, as good as the
Humankind maps look, they are not as functional as part of GUI as the current Civ VI maps are.
But
There are other ways to 'model' better looking maps, and there are individual aspects of the HK maps that would be wonderful additions to Civ VII (waterfalls, more elevation, more variety of vegetation).
One possibility, which I threw out long ago (in Forum terms), would be to model the terrain appearance on the romantic landscapes of the painters of the 19th century: not trying for any hyper-realistic appearance, but a different form of fantasy:
or:
Realistic-ish but exaggerated enough to be able to tell at a glance what you are playing on.