These are a few celebrities whom I would actually love to voice as new characters in future GTA games (such as GTA 6, etc.)
Torrey DeVitto-some new brown haired and brown eyed first female GTA protagonist that everyone's been talking about. I think she'd be pretty good for the job! She's also very sexy and could probably even seduce the cops or any other law enforcement officer as her "special attack", lol XD.
Joe Rogan-as himself, a standup comedian the player can see in bars. I really love Joe Rogan as well, I think he's hilarious and a great pick for a GTA game!
Willie Nelson and Kris Kristofferson-they'd be BY FAR the best country singers still alive for this job! Not really sure if they should voice as themselves or two made up criminals within the game though.
The band Anthrax (currently consists of Scott Ian Rosenfeld, Joey Belladonna, Charlie Benante, Frank Bello, and Jonathan Donais)-I love rock and metal music and I believe this band would be the greatest pick for it! Again, not sure as of right now who exactly they should voice. All I know is absolutely NOT any cop or other law enforcement!
Eminem-probably as some Random Event character who's a criminal.
John Cena-as a main antagonist law enforcement of some form.
Peyton Manning-as a secondary antagonist law enforcement of some form as well.
With all that being said, what celebrities would YOU guys like seeing in a future GTA game?