I for one wouldn't mind if they take time off from end game content and do a touch of work on the actual 1-50 (soon to be 1-60) content. Yes getting your first class/job to cap is fun and exciting. Unfortunately the other combat classes/jobs...not so much. For a game who's big selling point is only needing one character to do it all, they've certainly made it as un-fun as possible to do it. I actually rather make multiple characters to level jobs at this point because it's simply too painful otherwise.

My suggestion is this, simply unlock the sidequests when on a new class. Just only allow the exp reward that way it limits the items and money coming into the economy. And when a quest is marked as done on a certain class it can't be turned in again on that class. That gives players on dps classes something else to do besides the same 5 leves for 5 levels at a time while waiting an hour for a dungeon run.