Arterial burst/Blood for Blood. You boop someone with your weapon and it goes plunk. That's not a very vampire thing to do, and passes up an incredible opportunity to practice The Rule of Cool

Why is the The Rule of Cool important? Because people like to do cool stuff in video games.

If the animation for this move was that your character just busts out a super evil looking blood claw and throws a haymaker it would be like 20 times more sick. As a player who follows The Rule of Cool as the lodestar for his builds, this would become a BIS move. But only change the animation don't do anything crazy like drop a tick of damage or add a ridiculous wind up.