Bloodspiller should be an oGCD.

[whiteblade89]

According to LaylaBell on Mogtalk #107, it depends on the number of enemies, but it still can change.
On a sidenote, he also said that Blackest Night gives 50 blood even if the shield is not destroyed.

I would hope SE would at least be smart enough to make it scale with the number of enemies. Anything less and it would kinda defeat the purpose of having it build blood at all. And TBN will just have to wait till we can see it with our own eyes. I'm remaining optimistic until early access.