@Prof3ss0r_M1k3Ah, now THAT is a very valid and important point that I can certainly understand.
Since PvP and PvE gameplay will always differ to such a large degree, IMO (and I've stated this elsewhere in this forum right after release), they should have simply done what the Call of Duty people did, and that was to separate the earned XP so that whatever you earn in solo/coop is locked to that mode and cannot be used in the competitive arenas.
In fact, from we've all seen happen here after release, I think that the ability to do this has already been coded, at least somewhat, into the game...and this is exactly how they were able to so easily adjust/limit/shut off earned xp and missions in solo/coop only, while leaving it unaffected in competitive.
So, the ability for them to do what I've been touting for like 10 months already, IS there and has already been coded for the most part, It's just that they are cutting corners and refuse to do it.