I think the problem lies in Demichelis, in the 13/14 season when we won the league he seemed to thrive when Kompany was missing, its like the added responsibility really made him up his game and that was the most valuable thing he offered the squad, I seem to remember him playing particularly well away at Hull when Vinnie got sent off.
However last season and this season that seems to have gone out of his game which is a real shame, I think Mangala (as good as he is) needs experience next to him, someone to boss him around and tell what to do, then he looks as good as anyone (he is only 24) but Demichelis seems to either be to lax with him or too lazy and either way we can't afford that, especially in a squad like City's when you're looking for trophies every season.