Square doesn't want exp to be hard. First the exp update, then the DC/EP update, the empress bands, and probably something else down the line. Thus, manaburn, rampageburn, bones, freakin' THFburn are perfectly fine by them. If you can't get the mobs first, well... Does SE make multiple King Behemoths spawn at the same time, just so everyone can get a turn fighting?
It's when you start killing their end-game challanges as easially as one would kill an exp mob, that they have a problem. And when they have a problem, you have a problem. Generally in the form of a giant plastic/foam hammer.