I definitely think he's gotten way too worked up about the intricacies of diablerie. I suspect that's just an edge case that they didn't consider, which is the whole point of this sort of alpha playtest.
But damn. Nearly every other substantial point he makes in this video feels really bad. I don't know what the wider community is saying about V6, but if it's even a fraction as scathing as this, White Wolf is heading down a very dangerous path.