AD Fizz Nerf's why?

I'm not a fizz main or have played fizz in the last 2 months. I also haven't seen him in competitive a ridiculous amount, and have barely seen him in my solo q games at high silver low gold. Why is he being Nerf'd? As far as I can see as a regular player if he is overpowered it's in riot's in-house games, because i don't see him pick/banned 50% in competitive, and see him rarely in solo q. I just don't get the reasoning behind knocking ad fizz down a peg unless riot is trying to enforce a meta on certain champs. I don't mind if this is the case honestly it doesn't matter if it is, but they continuously claim it is not before more actions that prove that is not the case, i.e. (tryndamere, yi, and tristana to name a few). Don't hold ezreal as the shining light either, having one champion out of more then 115 that you allow to have an ap and 2 ad build paths doesn't show your open to it on other champions. I can't name any other champion that has a viable build path other then their main ad, ap, tank, or combo build. (They can switch an item or 2 but it's not a drastically different build like the others mentioned are). I just want this explained in a way that isn't he's to strong than listing their strengths. Most of these build's had legitimate and strong weakness's. (Tryndamere was low damage and had to split push away from his team, yi had to reset or was useless a stun killed him, trist had 1 shot of burst then nothing for a long period of time, fizz lost his assassination ability in exchange for sustain damage and tankiness a common trait among-st top laners already). I just don't understand the need for these changes and worry this will become a trend concerning any off meta build discoveries.