Very awesome, I'm glad this is already in the feature requests!
Is such a thing difficult to implement? I am no developer by any means, but would love to see such a feature become available. I would think because the "Password Strength" visual is already checking the 'strength' of the password, that the underlying basics are already in place to enable such a feature.
Essentially "If <password> != Strong, then deny password change".
By the looks of that feature request, it's about three years old now. What are the chances it could get looked at?