If we play 4231, I think we just need 1 CM.
IMO we are going to sign just 4 players (CB, CM, RW and ST). Also, I expect/hope that some of our players improve under a new manager.
How would you play with the new players assuming Rooney is going to be a starter?
I am firmly of the opinion that Rooney should be sold this summer. He isn't good enough to be a striker/support striker anymore and I am not too fond of him in central midfield. I would get Griezmann as a replacement.
For the midfield, I would let both Carrick and Schweinsteiger leave. That would leave us with only Herrera and Schneiderlin as our midfield options. With our involvement in four competitions, two starters and two back-ups are a must for the midfield. I actually wouldn't mind if instead of buying someone, we use Pereira as a creative central midfield option. If we don't deem Pereira to be ready yet, I would get Banega for free.
The rest: a CB, a RW, & a Striker are a must, imo.
We will not buy six quality players in one window. Even if your analysis is correct.
First the manager needs to decide where to play TFM. Will RoShaun Williams be included in next seasons squad? Carrick? Who will we sell? Rooney's future? Will we play 433 or 4231 or both? (I prefer 433 because it gives us more stability)
Let's agree that a powerful and tall CM alongside Smalling is a must. We also need a playmaker to replace Carrick.
This is my prediction up front.
Zlatan Ibrahimovic
Sadio Mané
I understand that it would be tough to get 6 players, and too quality additions, in a single window. Though, we need to get 5 or 6 quality players in the next 2-3 windows to be able to reestablish ourselves at the top and to regularly compete with the likes of Bayern or Barca.
I see the two youth players you mention as option for our central defense. Given that our options right now are Smalling, Jones, Rojo and Blind (who no manager besides VG will use at CB), even after getting a top CB, it will leave plenty of room for those two. I don't know see a future for Rojo here and I wouldn't bet on Jones staying fit for a considerable length of time (I mean 3 games at a time).
Keeping Rooney only creates problems; and if we are getting Zlatan, then those two old hags can't be in the same eleven.
Carrick only works if we play 433 and have two mobile & defensively aware midfielders on either side of him.
I actually wouldn't mind if we went 433. The squad currently is more suited for that formation.