We'll be left with 4 (four) CF: Morata, Mandzukic, Llorente and Zaza.
Mandzukic will be earning almost the same as Llorente and we'll be paying 15M for his transfer. If we sell Llorente maybe the loss will be less, but its still a loss for an improvement in our 2nd CF when there are others areas on the pitch which need a bigger improvement. And we'll be wasting even more money on another CF by bringing in Zaza.
Sure, Dybala will be Tevez's heir, but what if he doesn't performs? What if he picks up an injury? Who will bring the necessary creativity to justify playing with two CF upfront? Coman? Vidal? Berardi seems keen on staying at Sassuolo, and as good as he is he ain't a fantasista either. I like Dybala, I really do, but even like that he is an unproven young player who has never played on the big stage, and relying on him to replace one of the best players in the planet is a huge risk. And besides that, would Mandzukic accept to sit on the bench at this point of his career?
We could spend those 30M and whatever money we have left to bring a player like Oscar. Or a winger.