Let's say I'm level 19, and want to check out Stranglethorn Vale. I could, but when I arrived, there'd be no quests for me there despite only a 6 level deficit. What's wrong with trying to level in a zone a few levels higher than your current level? If I can take on the enemies there, there shouldn't be any reason why I can't take the quests there. I think it would make leveling more fun for people who want more of a challenge.