Innovation

They are old gaming modes, slick way for leveling up. Even the quests are all asking you to gain things in a surrounding area. Nothing in the world is immutable. MMOs should never remain static, unless our globe stop rolling round. More idea for MMOs, please.

Balance

We don't care if the number of people in a class are too large, but we mind that a class is much stronger than others. The classes, while cooperating with and seeking support from each other, are nonetheless checking on and competing with one another. It is the state of being ideal. Otherwise the balance of one game will be ruin and the life cycle of it will shorten.