It does make bad parties. They think they can take any monster out there. With a power leveler, they have much more mana than any mage out there in the Dunes(especially RDMs with Refresh/Convert). Because many a time you cannot take a monster because the more mana used, means that thats how much longer you can take the monster. That and that getting chains are HARDER without a power leveler or with a mage that does not conserve MP well enough.

For those that cannot find a healer, tough luck. Find one around your level so that they can work on conserving MP and not wasting it. Many a time, a party will take snippers around lvl 13. Why i ask them, and they would respond they can take it, only to die a little bit later asking what happened? Many a time, its because they had a power leveler that made it possible for them to take the Snipper at such a low level and that when a REAL WHM or RDM takes charge of healing without one, they screw up. And they will continue to screw up as they level up too. When you have a power leveler, you are technically already dependant on them.

Like you said, its bad when things are spoon-fed. Giving some newb a starter weapon isnt that bad, it just saves them gil. Its not like they wouldnt know how to farm or anything. Partying only comes with experience. Power level = Spoonfeed them through their first parties.