Disabling malware via hash or signature doesn't require the Notarization step at all. Server can tell clients to not run anything with hash xxyyzz and delete it. I mean, just think about it. If disabling stuff required the Notarization step beforehand, no anti-malware would have existed before Notarization. Nonsense.
I think notarization is just a more automated way to do this approach, e.g., otherwise Apple has to hunt down all the permutations of the binary themselves. It seems like it just simplifies the process? (It makes it a white list not a black list, so it's certainly more aggressive.)