Why does everything that does well in LCS get nerfed?

Recently there have been Leblanc players in Lcs and for that guess what rito has done. Nerfed her so her W does less dmg. Usually Leblanc players use their W to get away but the damage is making it to where its harder to kill in the early game, so now champs like Zed that still do damage have a advantage against Lb. They nerf sion because he has op health regen and now they are saying to rely more on your w. So now sion will most likely be abused in lane Idk how to feel just had to say that I don't think they should nerf everything that does well in Lcs cause lcs helps players climb and makes people want to play those characters so.