You know, if I were put in charge of Civ 7 development, I would not know where to begin. It seems an almost impossible task. Where do you take the game so that the result is genuinely Civ 7 and not Civ 6.5? All the things people have aired on this forum have mostly been fixes to Civ 6, not a road map to Civ 7. What will it look like? Will it be bright like Civ 6 or more subdued like Civ 5? What will the leaders look like? More animations or static art? These issues may not affect gameplay but they are vastly important to how the game is received. What you do NOT want is a game such that reviewers say, "This is just Civ 6 with a haircut."
I don't know, I have a lot of ideas and think many other people do as well. Starting with something minor like actually sphere-shaped maps (would have to have some pentagons in it though), ending with some ground shaking changes like full transition from yield base economy to resource based (with big focus on logistics) and making pops their own entity rether than just property of city ( cities would become more of a formal thing that just represent dense clusters of pops and urban environment and pops would become key entities of gameplay each act independently and have different properties). To come up with something new isn't the problem, the problem is how much of a change audience is ready to accept.