If it can do stereo;
If it can tap into the music on a local network (like my LogicTech UE Smart Radio);
What the frequency range is; and
What the maximum spl output is.
I surmise it will do stereo at ease as most advanced network speakers now have this pairing function....Apple is going after a large chunk of this home network speaker pie....Sonos and others will have taken notice.
It will be able to stream from an Itunes Apple Music library....via Airplay, which I HATE when it goes haywire BUT love when it works. It will not do NAS network playing seeing that AppleTV does not seem to natively support movie files in a NAS.
Frequency will be somewhat limited looking at the drivers at hand....the main woofer/subwoofer is small...but it will be heavily digitally manipulated thus the idea of traditional "frequency" as we are used to, should be thrown out of the window. I see that the high frequencies will be fine.
Maximum SPL...it will be loud enough for the masses but will it be enough for people accustomed to live music, I doubt it, but it will be sufficient. Some people will call small SET systems with fullrange drivers loud....while some people who have lost hearing sensitivity will call anything not loud enough.
I think the homepod will be marketed for those people in the younger generations who are into convenient music but not necessarily high fidelity type BUT who knows? I am waiting for its release and real live reviews but I doubt I will purchase it. Got too many systems at hand.