1) Maybe people don't want to spend 48 hours grinding away, hour after hour until level cap. Some people have lives outside of the game and so those 48 hours of grinding will probably be spread out over a few weeks. When someone set's to hit cap in as fast at time as possible they will find rhythm that gets them the most exp/hour.

2) Anyone who claims that being power leveld makes people "not learn their class" is delusional. If a person is bad, they are bad, power level or not. I can spend all the time in the world leveling a character and still use random spells when i have TP for them. Also if a player cares to do well in parties they will use all of their resources to learn what is best for their class. This means coming to the forums and searching through their class section and reading what others have found to be optimal. They will then try out the spec/rotation and modify it with what works best for them. It's not hard to use a spell and see the numbers that pop up, and then use a different spell and compare. Powerleveling does not take that away from people.

3) I think the claiming system should not be able to "shift" between players not in a group. I'm ok with other helping you out if you ask them to, but for a person to claim a mob and then lose that claim because someone want's to steal mobs is not right.