Of all the new shards, I feel like this is the most balanced, and the best idea. 5
makes it comparable to Vampire:
Advantages of Void:
Denies healing. Could really hurt fire stall.
Is not CCable. Few decks have repeatable perm control (or any >.>), while very many decks rely on CC.
Stacks. 'Nuff said.
Advantages of Vampire:
Does 1 more damage. Self-explanatory.
Heals you as well - very helpful.
Is fractalable. Couple decks rely on this.
Can actually kill opponent.
All in all, I think Void is pretty comparable to Vampire, which seems to be pretty balanced. Like the card a lot.