People expected Mata to be the solution to our problems when our problems are related to the midfield (lack of steel and quality), the wings (lack of quality) and the defense (lack of experience). Mata has certainly improved us but we're having to build a new nucleus. As van Gaal said, that takes longer than one month. This summer has been fantastic in addressing that lack of a core. If we could get Carvalho or Vidal before the window closes, I think we'd have a quality team again, but one which will take time to gel.
Mata's more your icing on the cake signing, but he was signed before we managed to address the key weaknesses in our squad so people have been underwhelmed, but watching our games objectively, he's involved in all of our build-up play and is an important source of goals and makes up a lot of our chances created from central areas.