Sated Devourer Yi is not op, you just have to learn how to play against him.
This is the jg's job. Pick a champion that is very good at counter jgling and just don't let him farm at all. Make it so he can't get sated until 25 or 30 minutes in, this means he will be a non-factor until very late in the game, take all the rift scuttles (Those give 2 stacks) and make sure your team makes dragon and rift herald priorities. All of their lanes will get virtually no help because yi will be busy trying to stack his devourer. End laning faze early, fight 5v4's if he is trying to stack his devourer. (You should be able to win 5v4s) Obviously if you let him sit in his jg stacking and give him all the objectives then he is going to be strong, that is like if you go into a lane and feed someone 10 kills. He's gonna be strong. Sure yi is strong right now but if you learn how to play against him you can make him unable to carry every single game.
top and
support and then make sure to deny the early dragons and rift herald so that he cant get those giant stack boosts.
That tasted purple :D