And to be honest, I wouldn't be surprised if one day, they took the series into space, like where you're playing a crew member on a space station and a new parasitic virus was found on the now inhabitable Venus, or some shit. And Umbrella want to study it, and you accidentally bring it back to San Francisco, at the newly built research facility. You know?
It wouldn't at all surprise me...
I could stomach a location such as a space station for a RE game, the RE universe has enough technological advancements for such a thing. Even the first Revelations game had a satellite (Regia Solis) used as a weapon to decimate the vessel Queen Semiramis.
But for it to be more feasible they should use an aerial station just as a segment of the game, like towards the last stretch of a game, think it should be something similar to an aerial base/fortress , and even the Resident Evil 4 betas had pitched some Umbrella base Leon would reach through some sort of zepellin ship.
For instance the main character would explore this segment similar to when in RE 7 Ethan travels to the destroyed ship but after completing that segment the character goes back to the underground section and the Baker house again for the final bits of the game and the final boss.
I think it would be an interesting concept if they made that aerial base just like that, a segment that would end with the base self destruct and the character having to escape it and go back to the surface somehow for a final section to explore and a final boss.
The MCU movie Black Widow has kind of a cool aerial base as the lair of the villains, and some action scenes where the heroes escape the base sinking to earth defying some laws of gravity in the process until they get inside choppers. For a RE game they could adapt a scene like that better refining the idea so it doesn't look glaringly unrealistic.
As for enemies types I don't care much if zombies show up or some other type, there has been so many different stuff and monsters already that for me personally traditional zombies no longer can be considered the standard RE monster, we had plagas, the mold, and so many modified virus strains throughout the games, and all that is canon now, so for better or worse, the fans and public in general will expect new enemy forms for RE 9.