Rito likes to buff odd champions...
For some reason, when a champion isn't played much, Riot likes to buff them.
For example, Ekko and Cho have been getting almost exclusively buffs. Why though? They aren't popular, but they certainly aren't UP. I'd be willing to argue the opposite.
Along with this, they really only nerf champions that are blatantly OP with a 55% winrate or so, while buffing almost anyone below 50% (besides high skill champs).
Sorry to say, not every champ can have above a 50% winrate, that's not how math works.
