This was a random idea, and I doubt Rockstar would ever go for it, but getting a GTA character like Niko Bellic on the roster would be pretty cool.
Or maybe an older GTA because those are thought of as more "PS" games, so Tommy Vercetti.
Platinums: Red Dead Redemption, Killzone 2, LittleBigPlanet, Terminator Salvation, Uncharted 1, inFamous Second Son, Rocket League