I would like to suggest that in addition to carrying national EAS on the NPR Squawk (News Advisory) channel that NPR also carry EAS on "Squawk Net", the Breaking News Channel. NPR stations could then monitor the Breaking News Channel on their Endecs and have a direct line to national. This would improve audio quality across the country ... at least on NPR stations and any stations that monitor them. The NPR News Advisory channel comes via legacy equipment that some NPR stations no longer have or maintain. I would think that all (or at least more) NPR stations have a permanent subscription to the NPR Breaking News Channel. NPR should also, then, do a weekly test to be logged by monitoring stations.
As far as that is concerned, it wouldn't be bad for all of the major networks to carry national EAS and test it on a weekly basis. During a national emergency their regular programming is going to be preempted anyway. And the cost of adding EAS to a network operation would be relatively minimal, I'm sure.