I absolutely agree with you there. I feel that Di Maria would complete us as a side with his direct pace and ability to dribble out of pretty much anywhere on his day.
And just as an extension of my point, it's fair to say that United have one hell of a midfield and attack. Replacing Carrick, Cleverley, Hernandez, Kagawa and Welbeck with Blind, Herrera, Falcao, Mata and Di Maria is fantastic business regardless of how much it cost them and how exposed their defence is going to be by better sides.
We've spent a lot of money over the past few years so we can't just suddenly point the finger because United are doing it now. They desperately needed investment for an immediate resurgence and they went out and did it.