A fair question. I do actually think Carrick is just a younger Scholes, which we do need with the ginger prince in the swansong of his career. I think Carrick will help us use the ball far more positively through the middle of the pitch. So many times last season we knocked it square in midfield or just kept losing it, one of the things we miss most about Keane is his willingness to always want the ball, all over the pitch, his will to dictate. Carrick has that, he always wants to be on the ball, he always wants to start something, and he has the ability to IMO.
However he's not a ball winner, and he doesnt have the boundless energy I think we miss. But hopefully that will come later. To put it really simplistically, you could say he's solved half our midfield problem, i.e use of the ball, the other, the winning of it back, still has to be sorted.