Antoine Fuqua for a P1 style. Because Tears of the Sun.
David Fincher for a P2 style. He's got that gritty city feel down, and he can get dirty.
Villeneuve for a border war predator film in the spirit of Sicario. Although he needs to be doing the next Alien movie.
Paul Greengrass for a government response centered predator film. Dead swat teams, interrogations, government laboratories, etc. The interesting stuff p4 tried to include but sucked at.
And somebody else to do a Punisher/Predator crossover in the tone of End of Days. I don't know if Todd Phillips could pull it off, but I'd be willing to give him a try after Joker.