On the defending side, and I agree he isn't always effective, Yaya does have two attributes that a lot overlook, his height, he quite often clears the ball away from free kicks, and he quite often prevents a player getting passed because of his style, and he isn't scared to give away a cheap free kick.
His height is a asset that's for sure but if we sign Walker and Mendy in the fullback positions we won't be as reliant on it, especially considering our record at defending set pieces even with a team of midgets in general.