I wouldn't go so far as to say they need an overhaul, but an adjustment to the dLVL curve would be advisable. Especially in terms of the Defense/Vitality calculations. They're trying to balance PLD with both hands tied behind their backs right now, and worse, by their own system. Any monster more than 10 levels above us (i.e. most end game content in existence) renders sizable differences in defense completely academic. I don't think the change needs to be severe. In fact, I quite like the concept of dLVL, but the effects are pretty crippling right now. Switching to a higher logarithmic base would work wonders.