Sadly DoH aren't much involved in the game. After finishing the main quest line for any DoH, the only thing available is the market which is at stagnate due to various reasons.

I think the lack of customisation is really what's hurting DoH role in the game. Introducing special effects to crafted gears will make my monk for example different from the other monk standing beside me. These special effects don't have to be game breaking but they can be helpful such as enhancing a weapon to add a 5% chance to inflict poison or an armor that can cast slow for 15sec on target when HP is lower than 50% every 30sec. Now the requirements for such enhancements can be rare items which are acquired through normal monsters (low drops), bosses and DoL (similar to treasure maps). I believe this will create more influx to the market and expand the interaction.

Of course I want to go through end game, materia, ELEMENTS and more topics but I feel I should leave it at here.