Lets think about the class system/Amoury system...

[Zantetsuken]

The OP has some good ideas, but I don't think we will see any changes.

Keep in mind that the current Japanese names for each class are directly tied to the Armory system and are named specifically after what weapon/tool is used:

Marauder = 斧術士 (Axe Master)
Lancer = 槍術士 (Spear Master)
etc.

And since the Armory system is here to stay, we won't see multiple types of weapons for each class (at least not radically different)

However, the relic system shows us that jobs can have different weapons than their respective classes (they auto-equip the job soul needed ).

So DRK could be another job for MRD but have access to Greatswords or Scythes where MRD (and WAR) wouldn't*

*just an example.. I don't want to start an argument over what class DRK should come from.