I wouldn't mind if they added some command to cancel a cast, if you are engaged you can't rest and if you are bound/locked up and engaged, you have no way to cancel. Not usually a problem with mages(I mostly have it on blu) but if the change is made then it would become much more of an issue.

I fully agree with the topic though, I always have to wait a good bit before I start any cast after having moved. And it would be nice if there was a bit of leeway.