They will keep running into problems trying to keep balancing the same in both PVE and PVP instead of treating them as separate entities, which they are.
The one issue that I have when people ask for separate balancing for both, is that I for one don't want to have different behavior across two sandboxes. Numerical differences are one thing, but having completely different function or feel is another. Things like ability damage/charge rate, ammo pick up per pack (NOT capacity) can be done, but the core of how the abilities work should retain parity between PvP and PvE.
There's always an option to drop the little clause of "against minions of darkness".