Why are we constantly changing/nerfing LeBlanc

Firstly I should say, this isn't a post mainly complaining about Riot nerfing the new LeBlanc. I and i'm sure some other people would prefer the old LeBlanc that wasn't being changed/nerfed every patch. I know people did not like getting 1 shot without any counter play (although some champions can STILL do that might I add) I think old LeBlanc was considerably more balanced than her current form. I know what Riot was going for, which was more counter play to assassins I like to think.

Rather than constantly nerfing this new LeBlanc why would you not just revert her changes, to where she was considerably balanced. Yes, she could 1 shot champions, but there was and still are champions who can do the same. I don't play new LeBlanc much because well, I can't. She's the MOST banned champion in the game right now so you'd be lucky to get a game with the new LeBlanc in a ranked game right now. I'm assuming we'll just be seeing more and more nerfs/changes to her up until she's completely unplayable or just isn't a champion anymore like some champions that used to exist.

I'm not complaining about these nerfs, trust me I understand how broken she is, i'm just wondering why Riot would ever make a considerably tiny bit op champion, into this monster we know now. Open for any discussion lol.