Better an enemy than an ally? If it's consistent, it's your fault

I've noticed that some players simply don't understand how to play with certain allies or against certain enemies. And if they haven't played those champions themselves then it's no wonder that they don't understand. There are other ways to learn the champions than playing them, watching replays, watching others play those champions, reading information on them. But usually there's so much to learn and remember that it's hard to retain it all for most people, if effort is even made in that regard in the first place. And there are a lot of people that don't try to learn the meta champions.

If there were no bans, would you really prefer blaming your loss on the champion you don't understand(Yasuo/Kayn) instead of the one that is in fact too weak(Sejuani) or too strong(Neeko)?

I feel like bans are more used on champions that aren't understood than on champions that are imbalanced. Maybe the training practice mode should enable all champions so players can understand more and improve their banning power.