The leveling process needs more more level appropriate content
I have been doing a variety of content to leveling my alt jobs to 70. However, once I actually get to 70, I have very little idea what any of my post lv50 skills even do.
Lets look at the main ways that people level:
Leveling Roulette - 95% of the time, you get a sub level 30 dungeon, where you just spam 1,2,1,2,1,2 the whole time.
PvP - Use a different set of simplified skills.
PoTD - everything dies in 2 GCDs except for bosses. Also no skills past level 60.
50/60 and Trial Roulette - 95% of the time get a 50 dungeon or trial (I'm really good at playing my jobs at level 50, but most jobs change dramatically going from 50 to 70)
Open world content (daily hunts or fates) - Opposite problem where often the target is a few levels above you, resulting in misses, which makes learning to play the class really hard (like when fire1 misses and you lose enochian)
Levequests - Actually get to play your class at the correct level! Except the experience sucks, and these stop at level 60.
Maybe it would be nice to have something like a "near level" roulette, where it would pick only form duties within 5 levels of you.