Champs to play mid lane!!!

So, not being a league expert, I'm trying to figure out whether to keep playing Zed or leave him and go for the mages that are super OP in my opinion. The Zed buff I thought that would have improved the situation but the matchups are still difficult to win against capable people. If you recommend hard-to-learn champions that can make the difference in a game you'd do me a favor (apart from yasuo because it's permabanned) . PS. I have Syndra in mind but it seems like a team-dependent champ.