This is never going to be an MMO where you feel satisfied or accomplished by defeating all of the content. FF14 just isn't that type of MMO. All you need to do is look at the mechanics, zero (gear or stat) customization, GCD, red outlined ae's to see that the devs couldn't create difficult enough content if they wanted to. Hell you don't even need a vague or better understanding of all classes/job skills to excel in this game.

You want to know something even worse? This game will never be more difficult than it was upon release, it just is not that type of MMO.

Sorry.