With this change, I am absolutely certain that further design changes are incoming for DK as a whole. As mentioned before, is it is now blood shouldn't be affected a great deal by this change, but Frost and (by a small amount) Unholy has some problems if they just produced this small change without touching it further.
Right now, it's sounding like a time regenerating combo point system, where (hopefully) Plague Leech and Blood Tap will continue to work as they are currently. I'm excited for the move if it's designed correctly.