Folks will figure out their jobs somehow, eventually. I dunno that there's much to learn in melee jobs anyway. The actual hazard of speeding through levels is when your weapon and magic skills are way too low and you miss most of your attacks.

There's nothing SE can do to fix this anyway. They can't force players to level jobs. You don't really need big parties to level up anyway. I levelled 15 jobs to 30 solo, and it didn't take all that long. Later I levelled them to 50 for the AF quests, some solo and some in groups. Still didn't take too long. And that was solo. Team up with 1 other guy and it goes real fast. Maybe not lightning fast, but insanely fast compared to pre-2010 levelling.