I drafted McNabb in the 2nd round (leave me alone!!) and finally watched an entire game of his, since I'm a Cowboys fan. It ain't him, at least not totally. He has nothing on offense. His WRs are absolute dogpoop. Watching the game the announcer would show replays and say, "He was high to <insert scrub WR>" or, "He was wide to <insert scrub WR>"... and it was a good thing because usually those guys were nowhere close to being open.
McNabb is killing me, so I benched him for Couch (yes, I won somehow), but I truly believe that he needs good WR-play to open the field for his runs, which in turn open the field for his WRs. So far, nothing in that offense is working, but I don't totally fault him (as much as I want to).
I think the Eagles are grasping for straws on offense, which is killing him.