Maybe we could make everything similar to the FATE reward structure where your rewards are dependant on your performance. The actual performance doesn't have to be a lot... let's say, at least 5% of the total party's damage (adjusted depending on role), just something to make sure nobody's afking the entire time. If you don't meet that, put a cap on how high you can roll on items and decrease exp and gil rewards.

idk maybe that isn't a good idea, but maybe it would help.