No we shouldn't because he probably won't last another 2-3 seasons, but you take Yaya out of that team and we wouldn't have won 2 premier league titles, 1 FA Cup and 1 Carling Cup... He is a big game player and in all the big matches he has risen to the occasion and rescued us from defeat. He is a world class footballer who I have been privileged to see at this football club. It's just a shame he didn't have the energy levels of a James Milner because if he did, he would be absolutely unplayable nearly every game. The ability he possesses on the ball is exceptional and we need to buy another CM so we can push Yaya further forward and give him more licence to roam and damage the opposition in the final third of the pitch. We practically have to buy someone else in order to get the best out of Yaya because he is THAT good.
As for the champs league, you put Yaya in a 3 man midfield in the champs league and he would have shone. You put him in a 2 man midfield and we suffer. Our aim should be to bring in the right player to accommodate the correct role for Yaya, not to replace him. Take Yaya out of our midfield and our central midfield is very ordinary.