I agree, them using Lumiose City graphics and whatnot would be pretty cool. I've always loved Castelia from Black and White due to how unique and city-like it seemed, but they've managed to impress me (as well as a lot of others, I'm sure) even further with Lumiose.
Though, I could imagine them improving and changing some things before incorporating, so that things don't closely resemble. If they're creating these remakes on a newer generation, I believe they'd be pushing their graphical style more, and with that, things such as buildings, trees, streetlights, and so forth would be looking more dynamic, I feel.
If they're planning to make these games sequels rather than remakes, I suppose things could be changed even further, with, as an example, buildings and whatnot being added or removed.