The sad thing about league balance...
Is that they don't actually balance the game to make it fair
they balance it to make it fun and new. That's why there is a meta shift every few months - to keep the game fresh, even if unbalanced. Riot KNEW the juggs were OP, and could have quickly nerfed them... but they wanted to change the game to a new meta to keep it fresh (previously it was in "transitional phase" from the tank meta, now with the new AD assassin item + TDR being op I bet we go back to league of assassins). It's also why champs like Zed, yas, ahri, kalista, thresh etc will always be either good or op, because Riot KNOWS they attract a lot of players, skins, and keep the game "fun", at least for those that play them. Riot is never going to go the DOTA 2 route of actually trying to make the game perfectly balanced, rather than having meta shifts and perpetually op/flashy champs - it makes money.