How many would you get in? I think another big churn of players may not be useful too. We may need a few more too for the squad, it depends who goes first. But I see those as the minimum requirements though
Lets look at the season just gone.
Kooman and Allerdyce both messed around with the defence,both tried and failed with 3 cb's and 2 wing backs.
We rarely had a stable team, changes being made weekly.
That unsettles players, so when they play well one week they suddenly find themselves on the bench or out of the squad completely the next.
Keane found himself trying to build a partnership with Jags one game, Holgate the next and Williams the next.
We had complete disarray in the full back position with Seamus and Baines both out, JJK did well, Cuco didnt.
Gana was paired with Schniederlin one game,then Rooney, the Beni, then McCarthy and then Schniderlin again.
Sygi was asked to play left wing, centre mid, upfront and the NO 10 role, then he was dropped.
We played an out of form Rooney in every midfield position there is, as well as playing him wide left wide right and CF.
Up until January our CF's were DCL and Niasse.
The current squad does need looking at, but IMO, not major surgery.
What we need more than anything is players to be played in their best position week in and week out and give the defence, midfield and attack a chance to build up an understanding of each others strengths and weaknesses.
That said we need
CB
LB
CM
CF