It's not a PU. For one thing, it's far less flexible - yes, it copies attack, but it also ignores all effects like momentum, adrenaline, creature abilities, etc. that make PU so potent. The 12 health is a way to make this thing hard to kill UNSHIFTED. But there are many other sources of CC besides direct damage - lobo, mutation, rewind, damage this when it's shifted to something fragile, etc.
And you're right, reversion is a cheap self-heal, that's intended. However, the limiting factor is intended to be availability of enemy creatures... for which reason I'll consider disallowing targeting of your own creatures. That would be a cheap way to get a swarm of Black Dragons out.
Did fix the name, thanks Kael.