Vuci & the midget should be gone before next season and we must go for a decent winger in 433, Pepe's condition is still a question mark.
How do we play the 4-3-3? Tevez on the left, Llorente in the center and the new winger on the right? What do we do (if we sell both Mirko and Seba) in case Tevez is injured? We'll go back to 3-5-2, bench the new winger and play Llorente-Quag in attack without attackers left on the bench?
We do need a right winger. We also need one starting LB or bencher CM. But even with such purchases, we will need 5 or 6 attacking players. For the 4-3-3 we will need 6 attacking players, while for 3-5-2 we need 5 for an ultimate depth. A striker should be sold only if we intend to buy a new striker as a direct replacement.
P.S: So far this season, what we lack is a right winger to allow us to play the 4-3-3, as well as a midfielder to fill the void left by Giaccherini's departure. I see no problem at all with our attack.