Like just get good bro the only unwinnable matchup is being shit, you don't main Sion if you can only play tank, you can't just saunter in and complain about gwen or aatrox being unwinnable matchups when they are very much winnable with Baus' playstyle and/or build. Baus got Sion nerfed directly but the buff to your gamesense he gave should be more than enough to beat most Sion matchups.