I think CJ's Mom is the most interesting,as her story is a strange mystery.
or..I would think Caesar would make a great protagonist,in a future gta.
or..I think Kendal would make a great..1st female protagonist,as she has fire in her soul.
Kendals story would go something like this..she discovers her mom is not dead,she is wrongly,
told her mom is being held against her will,being experimented on.
This info would enrage Kendal into a hunt finding her mom and the cult whom she considers the,
evil doers, so she teams up with a hand picked team and they train in martial arts and weapons,
to rescue mom at a hidden under ground cavern,maybe on a deserted island,or in the woods,
or you finish the ending.