Hello, as someone who is running a linux distribution that isn't in the supported list (Solus) I'd like to suggest that there be a universal image for edge. There are three main ways this can be accopmlished, those being AppImageSnapcraft and Flatpak. I think the best option is flatpak since that's widely used on more distributions over snap which is mainly associated with Ubuntu.
@DonaldCorbittA Microsoft team member is reported (on a Solus forum) to have said in a December podcast that support may be extended to additional distros after Stable is released, but Microsoft has given no timetable.
It is pretty unlikely that Microsoft will bother with .eopkg, of course, and I don't think that Microsoft will abandon .deb or .rpm, because those are the packages used by Microsoft's supported distros, Ubuntu, Debian, Fedora, and openSUSE. Microsoft's WSL support has not moved beyond those distros, so Edge-Linux support beyond those distros is an open question.
Like you, many of us are hoping that Microsoft will issue an AppImage, Snap or Flatpak version in conjunction with Stable, but no one outside Microsoft has any reliable information about if or when that will happen.
The best we can do is to keep requesting ... Glad that you are asking, too.