hm first of all, you dont introduce us into whether your aim is soloq or compatitive, i guess it is soloq.

to the challanger player talk, your argument is that on challanger lvl a 53% winrate is shit, while the statistic on only challanger games does not require enough games to get a good statistic, but i guess you mean that a normal chllanger player should have at least 55% winrate on a champion, and therefor if a champion has a bad winratio in challanger shows what? and tbh master and challanger are quite near, in fact there is often only a problem of time.

so lets jump to the shaco-ammumu talk, your talk imply that certain champs need diffrent game knowlage to be played efficiently and therefor every devision has their own strenghs and weaknesses, but these also conclude that other champions doesent, for example senjuani has over all a 57% winrate while in dia only 55%. and therefor still the highest winrate over all (leagueofgraphs), what does this show? that lower elos are weaker agains him and higher elos also, or does that tell you you shouldnt take senju jungle couse he wins only 44% of the games agains mundo(kinda ironic from me)? or katarina, why is her win rate over all and in dia+ the same if the game knowlage makes the diffrence? does this imply that more game knowlage does not give you higher carry potential? or is the champion simple in the same spot on both elos? pls make clear statements, dont say it depends, as thats what it does ever, it depents on the players knowlage, the teams knowlage, the league, etc... endless list.

but statistics even on higher lvl give us a good overview, they tell us many things, what are mostly tend to be more on the better side then on the "never trust a statistic" side. so statistics show us what champion is more likely to win the matchup, and also in what stage of the game what champion excells.

and now jump to your meta topic: you limit your example to lanes not entire games, so basicly katarina is a bad choice agains malzahar but in fact the chance of getting malzahar in lane is by far rly low, malzahars pickrate is 3% where katarinas is 12%, that totaly left out chances of certain picks and champion experience, an dia player who never played malzahar will not pick him into katarina even if the matchup would favour him. alot of players specialy in dia+ (well i am also only low/mid dia), and i count myself to these players, pick what they are comfortable with and know their scope. so for example a katarina pick can be also a better choice in terms of teamfighting, while the katarina player plays with the strenghs of katarina not looking at her weaknesses. your point is to optimistic its more like: dont pick katarina you will get a malzahar crushing you, else then: you have a chance of 1:1000(just an example) that you get countered by certain not popular champion. vice versa, picking a counterpick also does not give you a auto win just a advantage.

and now back to winrates in general: i am not sure about your advice, i am fine with you saying that winrates of higher elos does not apply to lower elos, but does that mean you should jungle amumu in lower elos or does that mean you should try learn shaco as his winrate in lower elos seems fine and with getting stronger you will eventualy get more benefit with playing him.

well if it comes to riot they dont balance arount lower elos especialy the lowest ones where the big playerbase is is left out, just becouse of the fact that it doesent matter to them.

you also dont go to the argument why these numbers are soo intressting for conversations, well in fact its the only sure thing we can get, we know nidalee will fall off late game (according to winrates), or we know certain champ is more likely to win certain matchup. so if we take that away, we have nothing to argue, as a statement without any proove is just like saying: god is a woman. these statistics are proove, and in fact certain champ wins 55% of their games in dia+, means hes strong in dia+, even if he has 54% win hes doing fine in these divisions, as these winrates does not cover a single player who has a strong winrate on these champion but shows that these champion peforms well along most players.

thats so far, guess this is getting a bit longer then expected.