OP/UP and unhealthy/toxic are not the same thing
Having numbers that are too high or too low is not the same thing as bad design. It's unfortunate that whenever some champion goes above or below the power curve and becomes meta suddenly they need a rework.
Yes, there are some strong or weak champions that legitimately do need reworks, but what I find strange is that I've rarely seen a meta go by without the several forums I frequent all saying how every powerful champ is toxic and needs to be deleted from the game.
Next time you complain about a champion, ask yourself, do they really need a rework or is it a matter of number tuning? No need to call in the entire workshop when a simple nerf bat will get the job done.