Viper has come back to Super with minimal changes like most of the original cast. From what i've seen her EX knuckle has had its speed improved and that's about it. Her new Ultra, Burning Dance, is very flashy, It's activated in the air and starts with a diving kick into your opponents neck, if this connects Viper will ride her victims face like a snowboard, flips them into the air, catches them then flies up into the air and electrocutes them.
I was actually looking forward to something more from Viper as her bad matches still seem to be extremely lopsided, even with her new ultra I don't see this changing. I hope to see more from Capcom before the game is released as I'd like to see a way to fight back against the Zangief's of the world.