We won't need a major overhaul in one summer, I actually think it wouldn't be the best option. It should happen gradually between 2-3 years. Until we get a set of wingers and a decent midfielder, I believe we'll be able to challenge for top 3 places. 3 first XI players would be enough for now imo. It would enable us to play Ramires, the new midfielder (a deep-lying playmaker?) and Mata as central midfielders, while 2 new good wingers give us a new dimension in attack. Those 3 players are crucial to transform us from the shit we are now to something decent imo.