No way. You can totally go out as a party and kill mobs pretty far above your level. Exp chains even work exactly the same as XI.
And it's all just as slow and stupid as doing it in XI post-Abyssea too!
Personal opinion and all that. There is nothing wrong with wanting to mob grind, even if it's a slower way to level. My advice is to do so but in instances. Think of it as mob grinding while moving around!
"The game is fun as **** to me and I don't need epeen DPS parsers to feel like a bad ****. " ~Curt Schilling (A.K.A Wyndwraith)