Sorry if this was already suggested... (I made a quick scan of topics on the first page and didn't see it) but I think that if you could get skill ups in campaign battle it may breath new life into it. As it stands now, you hardly see anyone else doing it anymore. I completely understand why too. Why would you bother going from one battle to another for 5-9K exp and no chance at all of a skill up when you could be in aby getting the same (most likely more) exp, better drops, (some needed for AF3) and skill-ups?
But Campaign was always fun, and more fun when there were a large number of people. Random parties formed in the heat of the moment with no care or concern for job/level simply made it memorable, and added to the idea that WE were all on the same side in the struggle.
Again, if this was already mentioned I'm sorry.