Exactly, which means that the Monk has a solid reason to go wisdom....or can ignore it. If the monk doesn't want to focus on Stunning Strike, and would rather spend KI for other places (such as subclass abilities perhaps) and ignore wisdom....that is now an option. Or....they can continue to pump wis for the best stuns. Both are viable, which is exactly the flexibility I am shooting for.
My main issue with that is it starts to push against the Barbarian's motiff. The barbarian gets a straight +3 to damage when he rages....it seems odd that the monk would just get a better damage bonus than the barb all the time. With an extra attack, we have the differentiator of having to use a resource to get those attacks, and lots of attacks is already established in the monk's core profile.
A more subtle option would be increasing the Martial Arts die to a d10 at 11th, and maybe 2d6 at 17th. This gives just a smidge more damage, but it also helps other abilities like the quickened healing and some subclass abilities, so its less straight damage and a more well rounded bonus.