I just saw good midfield with Ramires and Mikel being put in there and loled. They're decent backups at best and should be nowhere near the first team when the likes of Mario Gotze, Javi Martinez, Thiago and Schweinsteigger last season were rotating for games at Bayern last season.
Also City's mentality is a weakness, however you have not actually pointed out an actual weakness in the squad.
Would also argue that 2011 barca had a clear weakness in height, second they face a team capable of bus parking with a high work rate in the midfield(Chelsea, Inter and Bayern) they got shown up without having any ideas. Bayern 2013 had no weaknesses whatsoever though. pace, power, work rate and technique is pretty much unbeatable.
Also United winning the title in 12/13 is an amazing achievement.