I agree with the author, what AArch64 (or any alternative architecture) really needs to be taken seriously for more than "toy" or "appliance" type use cases is a real desktop board that an interested party could swap in place of the motherboard of one of their old PCs without having to invest in a pile of adapters.
To me, that means the following:
* Standard ATX or MicroATX formfactor * Standard ATX power input * At least two standard DIMM or SODIMM slots, preferably four * At least 32 lanes of PCIe 3.0 or greater, exposed as at least one x16 and one x4 slot plus one x4 M.2, leaving eight lanes for onboard accessories or more slots as desired * At least two SATA channels, preferably four * At least one copper gigabit ethernet interface * At least six USB 3.0 ports, preferably more and faster. * Onboard audio sufficient for watching Youtube or participating in a VoIP/videoconference call.
Since I'm pretty sure that providing video from power on rather than after the OS loads requires support in the video card itself, onboard video of some sort is probably also a requirement for now as well. Specifics don't matter, but it should be able to handle an accelerated desktop and video decoding.
onboard audio is questionable in quality typically anyway, being some strange monstrosity (ac97 lol... intel-hd-anything)