The problem is there isn't alot of progression milestones right now. In FFXI you had subjob @ 18, jeuno/chocobo @ 20, advance jobs @ 30, AF @ 50. Also you had garrison, eco warrior, missions, and quest to fill the gap between 1-50. Another thing was zone progression. When you level 1-50 in the same enviroment things can become stale.

SE is working on fixing these problem but we are still a few months off till we reach that point.