A lot of things are already present in CD to give it a unique take on the genre, so that certainly helps.
Hitting the ground as a level 1 Agent, then having to not only scavenge for weapons, but for orbs as well, all in an effort to level your agent while staying alive. Weapons would level up from killing other agents, same for explosives, driving could level up from taking gunfire and running Agents over (and would retain their ability to transform as you level the skill up, giving an incentive for vehicle focused playstyles), agility would be the classic orbs, and strength would get leveled when you either throw something at another agent or beat them to death.
Combine that with a fully destructible map on the level we have seen so far, and you have something special imo.
And just to spice things up, add in gang members as A.I. running around the map to give an alternate way of leveling up and some target practice during down time.
I would just be curious how they handle aiming in this hypothetical game mode. Crackdown moves too fast for normal aiming, which is why the previous two used a hard lock aiming system, but that always resulted in semi auto weapons with great range taking priority over a lot of the weapon sandbox, and having that in a PvP set up would actively discourage mobility, which is a huge part of CD.
