you know who hasn't fallen below a 50% winrate?
and 
Ahri is one of the most played champs which would herby lower her winrate due to more people being bad at her.
Jhin has only fallen below 50% back before turret first blood. The lethality changes ensured that most jhin players would be nearly garunteed to win lane, unless against the only adc who can zone out jhin... 
's utility alone carries him through a large majority of the game. Similar to how with
in that you only need ONE hook to make a play.
Winrate means nothing without playrate. The only playrate of kayle at the time of this post(according to lolking.net) is 1% of all of league players...
By your logic you are also saying that
is overpowered due to him having(again at the time of this post and according to lolking.net) a 54% winrate and a 1% playrate.
The same as kayle's winrate and playrate statistics.
Not to mention that if you count those two overpowered thanks to their winrate and playrate you also have to include
whom (gonna say it one more time at the time of this post at lolking.net) has a 55% winrate and a 1.4% playrate.
Just throwing statistics means nothing without actually taking in what they mean.
You haven't even proposed any types of meaningful nerfs to 
Evidently,you just want to change her numbers...
And if you change
's numbers you would have to nerf (by your logic)
's numbers,
's numbers,
's numbers and
's numbers
Which makes no sense as they are all balanced.
has the best earlygame of any adc in the game. Yet Riot still allows him to scale into the lategame... do we nerf him for having a good laning phase?
NO, because laning is one of his huge strengths that was intended by riot.
is one of the safest champions in the game... and you want to nerf her NUMBERS?????
nerfing numbers on a champion that has to NOT EVER get hit straight up doesn't work
pre-rework
and because it was gross for how easy a pentakill was to get.
Winrates don't constitute a nerf by themselves.
Make a sensible argument or don't try to argue a point which has no weight behind it.
P.S. If you are trolling, you are pretty bad at doing so. Just sayin, I can at least respect someone who puts effort into their posts.
Evidently you simply throw around the winrate like it's your "BRAND NEW CCCCAAAAARRRRRRR" from a gameshow and expect it to grab people's attention.
It did but you don't look the slightest bit intelligent from that style of writing.