Pretty interesting idea and i love it. But keep in mind that other bosses are nurfed, other are buffed(eg last boss SFK). So for this patch you can call ti balancing.
Heroics are easy for the good/geared players, hard for the bads/fresh, so for the average PUG its on a good shape and the dificulty should stay as it is.
As for your idea now. I beleive it would work pretty well despise the QQ that would bring(wanna be elitists will QQ that casuals will get more VP, bads will QQ that it is too hard). Amount of VP can be changed easily(5 VP for each achievement would be good eg) so with a little experiments this new feature will be a great addition for extra challenge.