What would happen if the top 50% of champions were nerfed?

This isn't a sarcastic or critical post, just a genuine question tied to a thought experiment. I hope it spurs an interesting discussion.

One of the best ways to better understand a system is to completely and utterly destroy it. If you push a system to its breaking point on any metric, you can witness and discover strengths and nuances that you otherwise wouldn't have been able to observe.

I think, even hypothetically, it would really, really interesting to see what would happen to the game, and how the effect it would have if riot dispensed severe nerfs to the top 50% of the champion pool (basically everyone with a win-rate higher than like 50.5%. I'm working off of monthly gold solo-q stats but the top 50% is more or less the same across all rankings). Not because they all need to be nerfed, but just to see what would rise from the ashes. Just from a cursory look at the list, I can identify three types of champions who currently reside in the top 50%:

There first are the champions who are always complained about by someone. They're the ones that everyone whines about, and often for good reason. Because of their kit mechanics (usually a combination of oppressive damage potential and high mobility) they go through cycles of dominance and disuse based on where they are in their personal nerf-buff cycle in comparison the current metagame (e.g. Lee-Sin, J4, Kassadin, Nidalee, Zed/LB, Riven). They're not always on top, but when they are they make sure no one can forget it. The term 'lack of counterplay' springs to mind.

The second group are champions who have just ALWAYS over-performed. Most of these champions (e.g. Heimerdinger, Malzahar, Anivia, Fiora, Swain) are the golden children of solid, unique kit design, and a dedicated, skilled player base (most of you know how goddamn terrifying Fiora mains are). The Majority of them haven't been significantly touched by patch notes in months or even years, and yet they have been in the top ~15%-20% of winning champions -regardless of the current meta- pretty much forever. They endure the changes to the meta, and often come out on top. They're 'sleeper OP'; not flashy, but very strong in capable hands.

The third group is comprised of temporary visitors. Champions who exist in the 51-53% win rate, and range from 'surprisingly viable' to 'not quite strong enough' depending on changes to the game-system as a whole. They tend to fall or rise based on power vacuums left by recently nerfed headliners, streamers promoting FOTM trends, and individual interactions with broader game-environment changes (e.g. Sejuani, who has always had potential, and hasn't been touched in a while, but is only recently seeing larger use and greater success due to the narrowing of the jungle pool).

Now Imagine if everyone who had a higher win rate than Yorick ( who sits at #61 with a 50.53% as of typing) was nerfed considerably. Almost everyone who is currently considered viable, or played even semi-regularly, would fall out of favor. It would be the game-balance equivalent of total, apocalyptic anarchy. And in the following post-apocalyptic wasteland, who would rise to the top? What break-out strategies and comps would players adopt in the scramble to re-stabilize? Would they try and use the 'next best' champions to cram into the currently existing meta? Or would the opportunity be used for the total re-invention of league as we know it?

This will literally never happen because Riot would piss off and probably lose MOST of its player base, and basically break their own game. But as someone who loves breaking game systems, It's something I think would be absolutely fascinating.

What do you guys think would happen?