We had Morata, Vlahovic (he joined in January didn't he?), Kean, and Dybala.
Now, we have Kean, Vlahovic, Di Maria, and Milcuck (assuming it's a done deal of course).
I'm not counting Chiesa because he's still injured, and you can include Cuads (one year older Cuads on an expiring contract) if you want. I see Kostic more as a LWB, possibly a LW, but we don't really know how he's going to fit/integrate into the system.