So why consistency is a sign of balance?
A consistent winrate of around 49-51%, sure. That's probably balanced. But what about winrates that stray out of that range?
Yes, this is about Ahri; or rather, a specific argument people keep bringing up. I've seen some people claim that because her winrate never really changed, she's completely fine and shouldn't be nerfed. But to me, the only thing consistency shows is that she isn't as affected by meta shifts. Is that indicative of good design? Maybe. Of balance? I'm not convinced. A champion with a consistent 60% winrate is obviously broken, and a champion with a consistent 40% winrate probably needs some help.
"But her winrate isn't 60%, it's ~53%!" Yes, but (most) people aren't suggesting she be gutted entirely. The most common nerf I've seen is a Q MS nerf, and that seems pretty reasonable.
I'm open to hear any arguments as to why consistency = balance, and I will accept it if they make sense, but at the moment, I'm pretty skeptical.