the problem is that Yuumi reqiuires one thing that No one is interested in....TEAMWORK. People come into matches, ignore and avoid their teams to chase solo 1v1 kills. They have no interest in working with the other players (who they see as "beneath" them anyways) then wonder why they lost.
I had a match where I was support and they blamed me for losing despite the fact they would actively avoid towers, they sit around and go for whoever has most kills. If there is an open lane, they will actively avoid taking the tower in favor of running bot lane and fighting each other over ONE KILL.
Then they turn around and blame the support because the enemy team knows how to take towers and the fact THE GAME DOESNT GIVE A FUCK ABOUT YOUR KDA WHEN THE NEXUS IS TAKEN.
^^^^^^^^^^^
This is why lanes lose, people are more interested in sitting around and showboating, then blame everyone else because the enemy knows how to take the nexus. And when we end up losing (because as I said, the game DGAF when the nexus is destroyed, its over) they will sit scratching thier head how they could lose the match with "most kills"
Its not the champ, its that yuumi requires teamwork, and this community is so self-interested in who has the most kills that they actively stab their teammates in the back because they didnt get to showboat like they wanted.
The problem is not with Yuumi, its with the irritating "yolo solo" free for all kids who dont understand this is NOT A FUCKING TEAM DEATHMATCH
You WILL NOT win just because you have "most kills"
you WILL NOT make the enemy run out of "respawns"
you WILL NOT win if you DONT TAKE TOWERS
and you WILL NOT WIN by going into a 5v5 game, and treating it like a god damn FREE FOR ALL.