I recently played with Samsonov Stratus Carbon, and I liked it alot. I also have and Viscaria and they play pretty similair but the Viscaria has noticable more power. So this would be the best upgrade for you in terms of power.
However, the Viscaria is just as head heavy as the Stratus Carbon, maybe even more.
Only the thing is that you said you feel like driving through backspin doesnt have enough power. I dont think Viscaria (or any other blade) will totally fix this for you. Because your setup is already pretty fast.
I think the issue is somewhere in your technique (but I cant judge because I havent seen you play). Try to focus more on your weight transfer against backspin, I think that will help you.
But if you really want an reliable upgrade I think you should go for the Timo Boll ALC. Its designed to be less head heavy with the Tenergy rubbers.
So anyway I hope my experience helped you a little and goodluck