I personally think that the boss FATES are strong enough but the ones with waves of mobs needs to be more tougher and last longer since they're being zerged too quickly that if you don't manage to claim your own target the exp and gil you get are weak. That is a challenge in itself however since most people tag mobs either with aoe or just hit it and run to the next one so that they can get any drops for having tagged it first, even if they don't do most of the damage. I've seen the same thing happen with quest mobs too.