Unnecessary runes reforged system that FUCKED balance.
Not fixing the shit leftover from Season 7 in an appropriate way that wouldn't lead to the massive changes we're getting now.
Zoe. Actually, scratch that, I like Zoe because she's good for the game. Accelerated total system failure.
True damage access on everything (conqueror was a mistake).
The shitty changes done to ADC itemisation.
The absolute mockery of a champion rework for my boi Aatrox when reworks like Irelia, Akali and Nunu exist to preserve and enhance the base concept.
The absolutele sheep/hive mind the forum community has (both boards and reddit)
The power creep and absurd damage meta.
The mind-boggling terrible balance philosophy that will lead to more balance changes being necessary in the near future once again (straight up tank buffs without addressing the issues on why they suddenly disappeared from god tier to trash).