Well why can't it be both?

It was both until until what, a week ago? I can't remember hearing anyone complaining about the fact that people were gaining too much xp grinding mobs in winterspring and silithus. If you want to enjoy the old world content, or BC content for that matter, and still receive appropriate awards for that, why shouldn't you be able to?
The fact of the matter is that incentive to move on to new content was ALREADY there, in terms of better quest items and higher amounts of XP from quest rewards and mobs. There was simply no need to nerf the xp gains from mobs once you reach the "level cap" of that content.
Some people liked Vanilla better than BC; some people liked BC better than Wrath. These people may still want to level to 70, or 80, or 85. But now if they want to level with any sort of efficiency, they need to leave that content they prefer, and go to content that they may not. That's why people commenting here are disappointed. If they want to level, they have to do it in the same place as everyone else... Why?