This is literally the first ever time since the game's release that viper has reached a 50% win rate in ranked. Before Yoru's release, she spent quite a while as the lowest win rate agent in the game. Right now her pick rate is 50.0%. Perfectly balanced, as all things should be. :)

On a side note, she is also the controller with the highest win rate right now (yes, she has a higher win rate than brim/omen/astra).

Source:

https://www.valorbuff.com/agents?timeframe=1