I think that's down to the fact it doesn't impose any limits.
Final Fantasy XIV has an undeniably slow start and initially feels very similar to other MMOs, but over time you'll have an increasingly diverse range of activities to do. I think that's down to the fact it doesn't impose any limits. On one character you can bounce between different Jobs (classes) that'll evolve into more complex roles as you level them up. This extends to your secondary Jobs, like crafting, fishing, cooking and more. Again, you can pick up whatever you'd like and just give it a go.