Di Maria was playing as a striker, so by the same logic - Blind, Fellaini and Di Maria could have done equally well.
As it was, we had a two man midfield of Carrick and Fellaini. I doubt Herrera being there instead of Fellaini would have changed the fact that we were outnumbered and dominated in the first half.
I like Herrera and think he will be a really good player for us, but he is definitely one whose reputation seems to have substantially increased while he has been out injured. He was/is a solid all-round midfielder - tenacious and tidy on the ball, but he wasnt the second coming of Messi. As
@Shimo said, in the games Herrera played we were playing teams that we should have comfortably beat. It may not been Herrera's fault that we didnt meet expectation, but his performances were obviously not so good that he single handedly dragged us to victory in those games, which is what folk on here seem to be making out.