I don't even want us to sign a replacement, we have Adriano and Lapadula but I see Niang very well as a starter for us in CF with a Cuadrado/Suso wing pairing. I don't even care if Niang doesn't score, it's the fact he offers physicality, dribbling, chances and kilometres that makes him so attractive, you can have another player be the fox in the box very easily. Conte's Juve is testament to this with mediocre players like Matri and even his Italia with Pelle. It's a proven model that works.
IMO Montella has the players at Milan currently to succeed very well. Montella isn't Mihajlovic who is a shit manager with no idea what he was doing. Look at the talents that we have:
Romagnoli
De Sciglio (amazing euros)
Mauri (star starter in Parma)
Donnarumma (someone Ventura is already raving about being the future of Italy)
Locatelli (finalist with Italy-19)
Zanellato (who they're calling the new Rabiot in Italy, Montella particularly really likes him in training)
Suso (came off a great season at Genoa)
Niang (20 and years of experience at the top flight)
Calabria
Milan isn't bad at all imo, we honestly just need a player that offers more kilometres as Poli isn't convincing and Kucka is inconsistent and as well as a new Montolivo/Pirlo unless Montella reactivates him into a new player. Abate/Antonelli/Paletta are solid and Honda/Bonaventura aren't bad either.
IMO this is a squad that can definitely surprise. Let's not forget the only team that has gotten stronger is Juve. Roma, Napoli, Lazio and Inter haven't invested into anything crazy