Pretty much agree with what Cata and GBM say.
Leveling has been made so much easier. This started to happen during the TBC expansion. With each patch questing became easier. Elite mobs that needed groups were nerfed, escort quests became just an AOE fest. I can see why Blizz has done it. There is just not the numbers of lower level players to support the more complicated game mechanics until you get to level 80.
If you are looking for a greater challenge then I would say run dungeons and battlegrounds as often as possible. They will give you much more of an idea what your class and spec should be doing.
Deadard Analisee (Director)
Ire Onic (indy specialist)