How about an explorer class, basically you go around the world of Eorzea and study various mobs and gathering nodes and by using the right set of abilities you will eventually uncover secrets about it.

With this knowledge you learn how to craft scrolls.

Scrolls would only be usable once, only 1 scroll at a time and will last X minutes.

Based on the type of scroll it would give you benefits when fighting a certain mob type or gathering a certain node.

Benefits could be anything from more exp gained or increased chance of obtaining more loot etc.