"darius needs a nerf, his mains have a 58% winrate"

The thing is that those "small" playerbases tend to be composed of mains. Popular champions naturally tend to have more people picking them up for a short amount of time. This lowers their winrate because it doesn't matter how OP Syndra is if it is your 3rd time, you are still more likely to lose than win.

Ahri is a bit unusual though. She is one of the very few popular champs that have a dedicated playerbase. This means that people who start playing Ahri rarely stop in comparison to other champions. As they get better at Ahri they achieve positive winrates and boost her overall winrate. New players joining temporarily lower her winrate but unlike other champions they are more likely to stick around, raising her winrate in the long run.

Compared to other champions Ahri has a very high retention rate for players picking her up. In the long run players are expected to go positive on a champion if they main them because they will be better than players that don't main a champion, even if said champ is FotM. Players only really lower champion winrate in 3 situations:

1. They are bad at the game/champion. This is influences all champions but some more than others. Ahri is a relatively easy champion to learn compared to something like Taliyah or Azir. This means that when you reach players of very low skill level the cut off point for going positive on Ahri after time is lower than some higher skillfloor champions.

2. They don't stick around. This is the most common cause. A player plays a couple games on a champion, does badly, and never picks them up again. Ahri is fun to play and has a high retention rate so she is one of if not the champion whos winrate is the least lowered by this. People like to play Ahri and keep playing her. That means they end up making up for their initial lowering of Ahri's winrate.

3. The champ sucks. This is actually composed of a number of different factors. Perhaps your champion is fundamentally flawed, that champion's winrate as a whole is going to lower. Perhaps they are weak in the meta, lowered. Maybe they have a low skill ceiling so getting better at the champ doesn't improve their winrate much after a certain point. Perhaps the champion falls off at higher Elo like Yi or Amumu. As you do better on the champion your champion gets relatively worse, effectively falling out of meta. This means the more you win the higher you rise and the harder the champion is to play until your extreme skill in said champion is evenly matched vs how bad of a pick they are.

Ahri is forgiving of the first, is hardly influenced by the second, and is currently a decent midlane pick who is safe into most matchups and is good at all elos. As such her winrate is inflated without her actual power being inflated. When talking about winrate on Ahri she is very comparable to those small playerbase champions because her playerbase functions like that.

i wanted to main morde this season the rylai changes just changed my mind quickly

so i took darius at least i won't fight with malicious over who's playing morde

which is why the nerf was bs

His winrate for mains was like 78 when they needed him for that reason tho.

if they do then this a really terrible idea

in dota2, the only time they balanced around mains was when Arc Warden had 94% win rate on his mains , because there was a build and if you did this build you won automatically and if i explained you why you would understand why

but mains having 60% win rate with a champ is just one of the most normal things i ever saw, no reason to nerf a champ for this