They weren't the greatest team on the planet a few months ago at all. Bayern were better than them last year but not by that much.
Since winning the CL in 2011, Barca have been in decline and a lot of that is to do with resting on their laurels and refusing to address the CB issue, as well as signing substandard squad players like Fabregas, Sanchez and Song.
The only genuine class player Barca have bought since winning that CL has been Jordi Alba.
Lets not just lambast Barca, Bayern have improved significantly to the point where they have 3 world class players in every position. The players all compliment each other. Robben always cuts inside so Lahm selflessly provides an overlap on the outside to give the defending full back another problem. Same can be said of Alaba/Ribery on the other side. Javi Martinez and Schweinsteiger work in perfect cohesion.
Make no mistake Bayern are as good as any recent Barca side in their prime