There is some true in OP. But it's true only if you can find one Lvl50 character, who want to spend his time for leveling you. If you don't have any friend than it's hard to level up. And power leveling so boring.
I dont agreed with OP. If you realy need to level up quickly you can do it, But if you just started the game you can find a lot content on any level, but most players do not want to see it, they just want lvl cap.
Realy, who of you defited Toto-Rak with lvl30? Or mid-level NM with lvl25? It's fun to do on apropriate level, fun and hard.