I agree that it's a bit too much noise. I feel like it's not really that hard to tell a target's current HP (with the latest revisions on PBE), even when low. Not difficult enough to merit creating the noise from showing the missing health divisions.
Perhaps see what a darker grey color would look like, but I don't think it's necessary at all.
Also, having played more and more on the PBE lately, the current HP bar revision on there has really grown on me. I'm starting to miss it when I go to Live.