Last patch, Sona had her Q and W potency lowered, but the cooldowns dropped. The potency of her shielding went up, and her speed boost to allies was changed a smidge too. Then, her self speed boost from E was increased in power and duration, while Q now lowered her CDR by additional amounts. This collection of changes skyrocketed her win rate to 58%. Let me reiterate. 58%. That's just absurd. If you expected Riot to NOT nerf any champion who can climb that high, then you must be in your own world. The hot fixes (which lowered her healing potency and speed boosts) were implemented last week, and the newest patch only wrote out and reestablished what the hot fix changed. Even still, she's a strong support, and has a very respectable winrate. It's no longer sitting at 58%, but she's still in a very good place. So don't complain.