Why cant riot give proper nerfs to tanks and supports?

Remember when janna got "nerfed" and then she had to get hotfixed twice after because those nerfs "nerfed" her into the 60% win rate area?

Now the same is going to happen to galio, they wanted to nerf him to make him less good general by making his Q do over 50% hp damage late game and making his burst higher than pure damage ap champs like ahri 4Head.

We cant actually tone down those classes can we? so much favoritism.