Leveling should be fast for your alt jobs or if you're indecisive and keep switching jobs.

On your first/main job, the level is irrelevant beyond keeping up with the MSQ as many other features of the game are locked behind the MSQ and certain side quests.

If you're level 32 and are still on the level 18 MSQ, then you only have content that you can unlock up to that point and you'll be synced down when you queue.

Fast level is not a problem in this game as you're not locked out of any content/reward for being overleveled (as far as I know as I don't do all content, ok, one exception might be certain endgame currency changes depending if you're at the current max level, but those hardly matter as you can still get the actual items).

Also, the faster you level, the faster you get your abilities, and too many people (I'm not one of them) have a problem as it is with having too few skills combined with the GCD.