Winrate is not a direct measure of champion strength.
If a champion does not have a high winrate, that does not mean they're bad, or even weak. It means that they either
A) Take time to understand B) Are FoTM and being played a ton by people who think they're simply a free win or C) Are best suited for certain team compositions where they become immediately broken. Champions that are only OK unless certain simple criteria are met, then they become insane.
If a champion has a higher winrate, that simply means that they're easier to play or understand or abuse than the others. A champion with a 55%+ winrate or 40%- winrate is a champion that should be looked at and understood, but between those two, I'd say that you can't really use winrate as a means to round out or base your argument on, because it simply won't work.
is in such a category where he is actually really really strong but not many people can utilize him very well resulting in a poor win rate. There's also
and
whose champions skill ceilings and floors are higher than champions like
where their power is more frontloaded and easy to use.