collection quests are not too bad on a 2 man team. I would set a limit though. If they want more than 6 or 8 of something I would skip it. I remember 5 boxing that gather 30 zeppelin parts quest in Hellfire because it gave a helm or something if I remember right that I wanted.

There are some collection quests that have 100% drop rates, those are not bad either, but I don't know a decent resource that will tell you what ones are.