Even if we do switch there's no way we're gonna see 4-3-3 as our alternative formation IMO.
Both Llorente and Tevez were really good and neither of them will be benched next season. So perhaps instead going after many wingers we'll go for 4-3-1-2, which can in a year or two more easily convert into 4-3-3. It will be much easier and probably more effective, if we buy a great player to play behind our strikers.