Incorporate crafting and gathering jobs inside dungeons, trials and raids. Something akin to FFXI assaults.

Example: Gathering certain items to craft a weapon, defeating a boss with said weapon.

Using gatherers to get through objects: (Copperbell Mines rock formations. Saint Mociannes beehives.)

Using crafters to create transportation through dungeons, creating barriers and weapons etc.

Possibilities and combinations would be entertaining to explore.