You learn how to play a tank at lvl 70, anything below it is just a child game, believe me.
I wasnt prepared for anything above 70 and i did a lot of dungeons and trials myself on my way to max lvl.

Its due to your limited amount of skills to use, some skill you unlock at 60-70 are so essential to the gameplay that you feel like playing different job when under lvl 60. You dont learn anything from that, just 1-2-3 into oblivion and aoe spam 1 skill.