There is absolutely no reason whatsoever for a 'leveling potion' to speed up leveling. To skip leveling and content? That's debatable, as they stated in the Fanfest, they're thinking of having a jump potion. (There's a whole thread for that so I'm not getting into it)

PotD has been, far and wide, the best addition for leveling. And you don't even need to gear for said place; simply go in and keep hacking at the dungeons until you get the arms/armor required to blow through the first 30 (or 40) levels of it.

Really, it's about an hour and a half, at most. And you actually learn your class doing it, versus skipping levels completely.

Nope. I'm poopoo'ing on this idea. Sorry.