So far we've gotten: LA, New York, Miami, and kinda Las Vegas and San Francisco.
But I struggle to think of any others.
Chicago is a cool city, don't get me wrong, but aesthetically it's kinda boring for a video game setting. I think Boston is too old to set a game where driving in a major mechanic, who wants to drive through those streets? Not Bostonians based on the ones I've met. And DC, nah fuck that!
Only ones I could maybe think of are New Orleans and Philadelphia. Honestly GTA Pittsburgh would be a risky but potentially interesting choice.
Idk, anyone want to play GTA Cincinnati?
I think philly would feel too similar to liberty city.
A return to the SF knock-off would be cool, maybe the bay area at large. Chicago, Pittsburgh, Detroit, or some amalgam rust belt city would be a vibe. New Orleans and the bayous work and rockstar did this in RDR2 already. They also did one of the early, top-down GTAs in London, which could also be fun maybe
But this will be in 20 years so it's a wash
Bay area would be really cool