Like you mean it could be fun?
This would not qualify as Civ 7; it would be Civ 6 fixed. Civ 7 has to depart from Civ 6 with some radical new feature comparable to moving from squares to hexes or single-hex cities to districts. Improving the AI is not flashy enough, even if it is what we (the players who post on this site) would like.
My own feeling is that the game might move to somewhere between 5 and 6. Cities in Civ 6 are odd. What is actually in the city centre apart from the palace? The government functions are all in the government district; the theatres are in the theatre district, and so on. You don't build walls round a city but round this empty centre. Look at any real city that did have walls, and of course the modern city sprawls well outside those walls, but a lot of functions are actually still within where the walls were. So there is scope for distinguishing between intramural and extramural development. For instance, up to the modern era, districts are created within the hex the city was founded on, then neighbourhoods spread out beyond the original confines. You don't need a lot of land for a diplomatic quarter; you do for a suburb.
It requires a complete rethink as to how cities work in the game - but this is why it would be Civ 7 and not a modded Civ 6.
No, it does not. We had 5 games in the series with pretty much cities working the same. There is no reason not to keep the new city building system (the best feature of civ 6) in 7, with some updates for example on how builders and repair work.
Personally I would get rid of charges, and instead make improvements cost money. I would unify builders, engineers, archeologists and naturalists in the same unit, make repairs fully automated (not requiring moving builders, but instead costing money and time to repair, and having negative effects in the meanwhile), et voila.
I would redesign WC (resolutions acting as resolutions and affecting gameplay, and being able to propose them); completely change religion (removing religious units from the game, but instead make religion work with trade, diplomacy and ideology systems); abandon the card like policy interface; and throw away the philosophy of adding modifiers, to use game systems that change how the game work in more meaningful ways (not all bonus need to be abandoned, but the philosophy of everything being bonus).
I would also redesign diplomacy (integrating grievances, envoys, favor and current diplomatic penalties in one single system); make a working AI designing it from the beggining with the full scope of the game in mind; add meaningful spy missions; add world wars to diplomacy options; implement things such as blockades, or allow closing sea/air and civil borders as separate options. I would also rework or remove agendas, and governors (allowing for true city specialization that allows tall play); and I would bring back vassal systems.
I would also remove the eurekas (so there is not a best way to progress technology, but instead choice), and redesign ages completely replacing the "points" and making dark ages a negative thing.
I would also add a health system and make the map truly dynamic so global warming can expand the dessert or change the land tiles; redesign how disasters and flooding work; and of course add earthquakes and tsunamies.
Also I would change the visual style, since lets addmit it, a new game needs to feel and look new to sell. So I would redesign leaders, units and the map to a more realistic tone. Not because I dislike the look of Civ 6, but because 7 would need a new direction to go.
Dont you think that would make more than enough to justify a new game? Cause 6 games in, there is no need to reinvent the wheel in every game, in fact no game has done it in the past.