Did anyone say it had to be an FPS? Because in Brute Force for Xbox 1, Tex could dual-wield rocket launchers, rockets and chaingun, etc. etc. etc. I liked the game anyway. Granted, he had super-mongo retard strength or something, but still, a flimsy pretext is fine when it'll let me dual-wield rockets, or miniguns.
Resistance has a good system, but really it'd be tough to dual-wield without auto-targeting or having to hold still as in Goldeneye. Even so, Halo with dual Grav Hammers would be 31 flavors of insane.