@DragonKingReborn : Well you'll always have trolling, to some extent even from your friends. Well, at least from MY friends, but we're all dicks to each other for are mutual amusement. But that is more in talking not actually screwing up each others games so even there I dunno. Now, if a story co-op had some kinda match making I wouldn't touch that with a 10 foot pole. Screw trying to play my story campaign with a random.
I want both styles to be honest. I'd love campaign to allow me to bring in a buddy or 2 (or more likely me join my friends game to tank for him). But for general co-op with matchmaking I'd prefer randomized (enemies) dungeon crawlers, or arena wave stuff or whatever. But I'll be happy with either, but the latter would ultimately get more play time out of an online community then pure campaign co-op, but I don't think that means it shouldn't exist. Both should, far as Im concerned.
Course, I'm ultimately here for the single player story so no MP is a shrug from me. I don't 'really' care if its not there, I just would play the crap outa it if it does exist.