We need the following as far as I can see;
A cultured centre half who is quick. We have three killer centre halves already in Rojo, Jones and Bailly.
Somebody who can do what Carrick does in terms of distribution, holding the ball and stopping the other team playing. I would still give Carrick another years deal myself. I quite like Dyer from Spuds, but he'll be expensive.
A striker who can score 15+ goals a season, as I assume Rooney is off and who knows when Ibra is back. Hopefully Griezmann.
If De Gea is off then another keeper.
If Darmian is off then another left back/right back.