If they do introduce leveling potions, I hope that:

1) People get a brief "this is what happened up until now" cinematic if they didn't complete heavensward or the original realm reborn, so they'll know what's going on story-wise
2) They have to go through a series of basic instruction on their abilities - like an enhanced Novice Hall (would be funny if it were taught by Faust!) to show them what the actions do/best times to use them (Yes, I know we can read tool tips, it doesn't mean everyone does). Some of us learn by doing.

I hope we do get them, personally, because I have two alts -- one of which I slogged through the story a second time, but swore I'd never do it again on a third. Not that the story is bad, mind you, it's just that I already know what happens, and although my character can be everything, my inventory tells me otherwise.