I'm part of a group trying to increase the AREDN adoption in New England. One of the problems we've encountering, and which I've heard complaints from multiple people about, is that the hardware list supported by AREDN changes too frequently, and hardware becomes obsolete before we can move through the logistics of getting it deployed in the field.
I understand that one cause of this is the increasing memory footprint of the AREDN image. Perhaps there are additional reasons as well.