Before I start let me just reiterate, this is not a dig at Riot's balancing department, this is just a discussion that I really wanted to talk about.
So I was playing a game with azir(yh I know one in a billion people that play azir) and I was decently fed (8/5/10 I think) and it was lategame around 37 minutes and I was full built and level 18.
We were in a teamfight and I two shot their lucian and the next thing I see in chat is: SO BALANCED!!!.
Now we all know that azir is basically and was in the garbage can for the longest time however this guy thinks that he is not balanced just because it is lategame. This is a concept that I wanted to talk about. People have a dig at riot's balancing team however what they don't realize is that this game will never be balanced. There are 136 champions I think and there are 5 slots a champion can play. That is so many combinations of champion roles and playstyles which makes a champion balanced in one place and unbalanced in the other. If you add the amount of items a champion can have (6) you literally can counter any champion that isn't balanced through a change of items.
Take this example. Say you are against Vladimir and you are playing Kayle. Before you get executioner's calling you have no chance of fighting him but that 800 gold item is what allows you to completely destroy him in a 1v1 because a huge part of his kit was decreased by 30%
Another example is fighting items with items. Take this. You are an ADC fighting a thornmail rammus. The only way in which you can hit him without taking your entire healthbar worth of damge you have to get a bloodthirster or some sort of lifesteal item.
There are so many combinations and variations of items that can counter one another that it is physically impossible to balance all the champions completely(so for all of them to have a 50% winrate).
I just wanted to put a concept that I find most league players struggle to comprehend because of A)salt and B)lack of game knowledge. Anyways thanks for reading :)