I just want to note: Many abilities have changed functionality in PvP. If allowing a single move-and-cast in PvP is too much, they could disable that aspect in PvP.
Anyway I'm hella in favour of this. As is the only time I ever use it as a WHM is if it's one of the rare unavoidable AoEs I need to be healing through that also, rarely, would interrupt my cast (Most "Large Unavoidable Raid Damage" skills seem coded not to interrupt, or maybe I'm just lucky?)