It looks like you're new here. If you want to get involved, click one of these buttons!
Most MMO's are designed these days such that you follow linear paths through linear maps hemmed in by invisible walls or conveniently placed parts of the environment. The quests are designed as a means to reach the endgame in the swiftest and least taxing way; the journey does not matter anymore, only the destination.
Having traditional levels forces you to move players as if on a conveyor belt from one area to the next slightly harder area. And those areas you have left behind become ghost towns rarely to be revisited.
Once at cap the game is played out in a hub town, a few raid instances and a handful of battlegrounds. 90% of the game map is rendered redundant to most of the player base.
The idea of developing or improving your character by grinding through traditional levels in itself is an illusion. The environment in the new areas you enter keep pace with the level of your character. Whether you are level one fighting level one mobs or level 60 fighting level 60 mobs (or wearing full raid gear fighting a raid boss) is largely meaningless; is is just a matter of semantics. The comparative difficulty remains broadly the same. Why not just remain as a level 1 fighting level 1 mobs? Why bother reaching an arbitrary number to fight mobs of that same arbitrary number?
Removing traditional levels would have one huge advantage; it would mean that the whole of the map could be accessible to all of the players all the time (unless other prerequisites were required to access areas). It would also enable a fairer implementation of pvp and raids without elitists (with a lot of time on their hands and little talent) dictating who plays.
Now don't get me wrong, I do believe that some goals are required; but these do not to be traditional levels. They could be, for example; small incremental improvements, locked quests or dungeon depths, rare skills, exploration, badges, titles, aesthetic items, mounts, pets, politics, economics, construction etc.
Let me have your thoughts on the above.