Running out of leveling content.

[Akujima]

The difference is WoW planned for people like you. You get bits and peices of story as you level. In FFXI, the story is something you do after you level (as you don't get muhc/any EXP while doing it).

And that's why WoW is a more successful MMO. It forces you to go on an adventure, and gives you incentives for doing so. SE should take a lesson.