Sona isnt a viable midlaner. Sona's waveclear is a joke. She has 2 damage abilities that hit minions. One is an enhanced auto. The other hits 2 minions. Her ult doesnt even hit minions.
Janna and Lulu have better waveclear than her.
why are sona and soraka allowed to sit at a comfortable 53-54% winrate for so long?
Its more of the problem of the meta. Basically any healer support is going to have a good winrate. Needs bigger changes to items and the game in general, which there isnt really a point of shaking that up when preseason is around the corner.