Everything needs an APS these days, and some sort of self defense capability against direct attack UAS.
Kongsberg has made it so these RWS can be linked into a sensor network for effective usage in a LLAD/C-UAS setup. As I understand it, for the system itself it is just software - allowing it to take input data from either onboard sensors, or a larger network.
The GAU-19 is a reasonable replacement for the M-2, same caliber, higher reliability, higher cyclic. It is already the APS weapon of choice for most manufacturers.
From my understanding the CA intends to adopt something like NGC2
Next Generation Command and Control (NGC2)
Which on the APS/C-UAS front will allow cooperative engagement down to individual RWS systems by AI/ML to Locate, Identify, Prioritize, and Engage.
There are so many different types of UAS, that defending against all will take a wide variety of systems.