I have this concept for a VR team battle game where you have to learn to actually cast spells through complex real time action. Like a mix of moving your hands in patterns and adding elements via hot bar in sequence and saying words via headphone. 1 on 1 or team vs team strategy game where complexity makes stronger team spells and counters. You could have casters who specialize in defense, offense, healers, traps and counters and how you build your team makes for strengths and weaknesses.