You talking player win % or Champion win %?
Overall I feel Win % is a weak stat with low data size. 100% win rate out of 1 game is not really impressive. Grading a high skill cap champion by their majority win rate when its something like 98% of the stats are tracked from players under 51 games does not always represent how well a champion can be played.
As crazy as it sounds to some of the more angry players on the boards end of the day skill matters in games of skill even with some RNG elements like teammate. Hell when you do the math the odds of the worst player being on your team are provably lower with one notable exception. If your the weakest link.
So I want to try to convince more folks who use the boards frequently to adopt the analogy of 10 Dice rolls over 1 coin flip. This sets a lot of groundwork for how you can prove to frustrated players there are opportunities to adjust their own impac, highlight some common logical errors people make, and the entire time you can still account for how much it fucking sucks to get trash teammates and the high impact they make on your ability to win so a frustrated poster can still get some validation.
It can help players understand how to improve far better then "Git Gud" or its "all luck." There are two easy ways to focus on improving, Narrow your Range, even if your top end skill does not change, you see a impact on your ability to win over a string of games. This is not mentioned as often as the standard improve your best case "carry harder!"