There should be separate loadouts for PVP and PVE (although it's too late now). All the guns you get in PVE stay in PVE and all the guns you get in PVP stay in PVP. Obviously the weapons you get in PVE would be more "extravagant" and more "unique" and then the guns you get in PVP would be more basic, with aesthetic differences rather than power and perk differences that the PVE guns would have. If there were two separate loadouts people wouldn't be bitching about it one way or the other... Then again, the ones who complain would probably just find something else to complain about in the end.