lets be honest Batman is a fighter rouge monk artificerI would argue that batman in the Animated Versions is a rogue....and I think that's part of the problem.
yeah the rogue with d8 HD and getting half damage form 1 hit per turn can tank better then some d10 classes.The modern identity issue of the monk in 5e is its a rogue wannabe more than a fighter wannabe. The monk is fast....but the rogue can bonus action dash at will. The monk is evasive, except the rogue gets evasion AND uncanny dodge. The monk is acrobatic, but a rogue with expertise is more so.
I wonder if there is an unarmed rogue subclass that could pull it offIn 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).
If you want to play a more grounded martial arts, play a rogue or a fighter. Give them unarmed strike as a ribbon and your good to go. A monk should be the anime esque Wuxia motiff, because right now its just a badly watered down rogue.