Lots of talk about Vamp Stiletto. This would make for a great (potentially anti-FG) Titan deck, though, too. If you had a rainbow stall, PA a Titan + Soulsteel any large creature (you could Chaos Power/Bless/Rage Elixir it too, in a rainbow). Complicated strategy requiring many cards, but a deck with lots of healing and a good shield could pull it off. It would be a great new way to defeat gods like Gemini. I think it would be a good card, but I am not seeing it as wildly overpowered.
Vamp Stilettos have been talked about as the most overpowered use for this, but that requires a substantial amount of quanta and the right cards. Plus it would take a third element to PA. If we are talking rainbow/trio to protect it, then it would definitely take long enough to develop that I think it would be fair. A lot of healing, yes, but so too is Fractal/Vampire, and that's not a tremendously popular deck. Tricky set-ups always have some difficulty to pull off. If it turned out to be overpowered in practice, then I think a cost bump to make it so that you couldn't play it with just a mark would compensate.
Speaking of PA, does this keep the same stats when stolen? And was there a decision about flying? I can't remember reading one as I read through; there was so much back and forth. I suppose those are things that would just be up to Zanz if he ever actually makes the card, so it's not terribly important.