i think a lot of the balance problems came from riot not admitting they did something wrong
so from what i can think of (currently) is there were 2 champion reverts when the reworks didn't work.
(don't get me wrong, not saying in lb's current state she is balanced but for arguments sake her rework was bad.) now, i dont recall at any point where riot reverted a change they made that the community hated. altho i've noticed very very few people actually use boards, most people don't even know they exist. i think if riot was to revert things that were hated instead of consistently evolving them when the previous evolution was dogshit then people wouldn't be so angry at riot and they wouldn't make the game so much of a 50/50.