True, as an out and out winger he was really annoying and I know a lot of Bayern fans who wanted to see him benched. However, as a CM he's brilliant in reading the game and moving into open space. In 11/12 until he injured his shoulder, we've seen him very often doing exactly that. Lahm played left back and Boateng as right back didn't add a lot in attack, so when Müller was moving inside, Schweinsteiger filled that space and created chances. He doesn't need to create a lot from out wide anyway, because Messi will move inside with the ball at his feet and it's enough to give him defensive cover and another option for an easy pass, Schweinsteiger is perfect for that role, imo.
Where's Müller, Fergus'son
. Every team is better with Müller in it
.