Hmmm, this wouldn't quite work in DS2 because you have many party members. If it was incorperated, that would mean you could almost infinitely cast powers.
While it would make sense in a 1 player kind of point, I rather want few powerfull powers than many weaker ones that can all be used at once, so you really have to make them matter.
(As an interesting note, the DS2 beta allowed you to regenerate powers through any damage done. Which included crates. Made them severly overpowered as you could just use them, chunck all the crates in the area and then use them again 0_0. So they definitely would have needed to be tuned down for this to work, which probably makes them boring.)