Yes,
You asked for constructive discussion and I disobeyed
Well I would go for Classes. Like special abilities, or even Class Skill Tree.
Veteran - Average range DPS/Tank Spec
Survivalist - Melee/Short range DPS with more CC
Outlaw - Long range DPS/Healing spec
Machinist - Tank spec/ average range DPS
What skilles? I don't know, maybe for example:
Machinist, Defensive stance +10% armor, -5% DPS
Outlaw, Sniper stance, +25m bullet range, -10% reload
Something like that.
But still, I don't have problem or strong wish to change actual system.
Class system would be attractive to me since I like to make my Character more personal. But for now it is also possible.
Edit: I think I could messed Survibalist with Outlaw, I don't remember which of them starting with Shotgun.