While excellent points it's REALLY a style over substance thing. IRL dual wielding almost always leads to less hits then using a single weapon because it's very difficult to control two weapons at the same time. Yes, there are rare people that can do it, but the other 99% of us really can't.Actually I see two major reason why V should be able to use dual weapons:
-Style over substance.
-For smartguns where aiming isn't even a point it would mean twice as much damages without much drawback.
Besides there's are SIGNIFICANT animation issue in a game associated with allowing players to dual wield.