Demichelis is a decent defender who has been scapegoated by both the media and some of the fans who refuse to blame other players. If Demichelis is within 10 meters of the ball when an error is committed by another City player, he automatically takes the blame. He deserved to be sent-off against Barca but did not create a penalty, and maybe with a free kick it would have been a different game. Also, today's "error" was in no way a foul or a penalty. He is experienced and a good ball-playing defender but he is slow due to age and easy to overtake by faster, more technical players.
Btw, is it just me or does every single referee we have had these past few games a complete moron, in Europe or otherwise?