The only jobs that have gotten more fun for me at max level have been DNC and BRD. The rest have only gotten more disappointing for me the more skills they added.

BLM I wish I could keep at 50 forever, it's 69 right now and I don't enjoy it... honestly I should probably just be leveling it through daily allied raids - I wish I thought of that sooner, actually.
I had more fun on DRG somewhere around 50~60 too, it's 79 now and I've lost all interest.
DNC is fun at low levels but actually gets more fun at high levels.