I don't see this happening anytime soon if they even considered it. It's not easy to just 'change' a skill. Have to spend dev time on it including animators to make new animations for each class that can cast on the move using this ability. Requires a bit more time then you think. Also, it would not be a high priority on their list.

I agree it would be a lot of fun, but just don't see it happening with everything else the team is working on.