You could make a case for revising DRK's resource system, based on the fact that MP regenerates during periods of forced downtime while most gauges do not.

Dark Arts was fine as a concept but its principle problem was around the frequency of use. For it to have any meaning over the current system, you need to be able to use it to situationally choose between two equivalently useful effects (i.e. physical and magical defense). I'm always wary about stances in this game, given how much it has historically struggled with registering stance changes.