It's been a few days already that the Teamfight Tactics community is complaining to Riot about the Kassassin composition. Yeah, you know: give a Youmuu's Ghostblade to Kassadin — thus making him an Assassin — and watch him obliterate your opponents. Kassassin composition is nothing new, but patch 9.18 reignited the passion for this specific composition.
However, while it's super frustrating to play against, according to Riot stats the winrate of the composition isn't abnormal — which is explained by the fact that a lot of players actually tried to play the lineup without understanding how it's working. Obviously, they couldn't reach the top 4, and their defeats affected Riot numbers.
Mort has said win rate isn't their primary influence on whether something is OP or not. Riot look "at how often a champ shows up in the first place comp."
In the end, Kassasin composition feels broken because of the ridiculous — even nonexistent — margin that it left to counterplay. The problem being that nerfing Kassadin himself won't change anything... Don't you think?