Poppy was "OP" but characters like Riven aren't?
I have no understanding of how Riot Buffs or Nerfs champions. AP Trynd has a heal and does next to no damage? BETTER NERF IT. AP Yi is hard to kill and counters Meta Lane Champs in a game where counterpicking is important? BETTER NERF IT, CLEARLY TOXIC TO GAMEPLAY. AP Sion? Not going AD on a hero like we wanted you to? BETTER NERF IT. AP Poppy being able to kill heroes and having an ultimate that changed how people had to play to counter it, thus opening different ways of play and making other heroes more viable to choose against her? BETTER NERF IT.
On the flipside: Riven, a champion with unfair levels of mobility, high health, a very strong burst and even has an AOE stun? Nah, that's fair and balanced. Characters like Teemo that have a kit designed just to infuriate and annoy the person you're laning against? That's a POSITIVE addition to our roster and not TOXIC to gameplay at all!
Why are the heroes that are slightly outside of what Riot wants nerfed into oblivion or reworked to the point of never being used, but characters that have been in the meta for multiple seasons and are always strong picks, regardless of the team comp, left as they are? Riven, when she first came out, had next to NO damage on her Q, it was purely for her passive and the mobility it gave. Now it's a Mash-To-Win button with loads of damage and a knock-up inside of it. Is this the kind of hero and meta we want in LoL? Mindlessly overpowered heroes with huge power spikes on easily acquired items (Corki with Sheen/Trinity Force for example. His damage SKYROCKETS because of how absurdly well it works with his ultimate. Pun intended.)?