Level Up & OSR Enthusiast
It's how WotC does the job. 5e doesn't have to use spells for supernatural abilities. Plenty of 3pp prove that.In terms of the core "ninja esque martial arts guy".... the rogue just does it better. So to differentiate, the monk should go Wuxia. It should be completely mystical, and yes in 5e terms that means it probably shoudl have more spells (I know some people hate that but that's how 5e does the job).