It makes so much sense with Monk, especially with their lore.
For one, Mistweaver has been two specs forced into the same tree forever now, and it causes a lot of frustration in the monk community as fistweavers and mistweavers argue about the direction of the spec and how it shifts from “fistweaving patches” to “mistweaving patches” etc. This is the perfect opportunity for Blizzard to take fistweaving and make it a supportive DPS with heals and buffs.
The precedent is also there as well. Considering there are FOUR different celestials with FOUR different schools, having Chi-Ji the Red Crane (usually affiliated with fistweaving talents) and Yu-Lon the Jade Serpent (Mistweaving casting talents) being sliced in half and crammed into one spec ruins the feel of actually invoking different celestials.
Its quite a simple solution, and Blizzard already has the groundwork there for a fistweaving spec (tho i reckon it might be harder to make Mistweaving an isolated spec as they would have to consider making it a ranged caster, which would be pretty cool in all honesty).
I think the game will need more support specs sooner rather than later, as it stands currently everyone is just going to be sitting around waiting for Augmentation Evokers to join their groups which will get stale quickly.
In essence, I am suggesting the following specs for Monk:
Xuen - Windwalker
Niazhou - Brewmaster
Yulon - Mistweaver
Chi-ji - New fistweaving spec
Thank you for reading 
