Had a weird trial game with him, we lost absolutely terribly, but it really wasn't due to him... IMO yi is a snowball hero, in that unless the person playing him is retarded, which burningdust most definitely is NOT. Yi doesn't really make a difference, unless your team is already winning, in which case yi is able to effectively shine as a damaging champ. I would suggest another trial game to gain an accurate representation of his abilities, as what I was able to see was good singular game play, and a good concept of not over-extending, but I was unable to see, for better or worse, and type of team-playing mechanics or actual offensive play.
Because I was unable to see these mechanics due to the game, and not due to the player, I lean towards a yes, but would like to see another game to make sure that he is actually able to play a strong offensive game.