Both platforms already exist, being the xenforo.com website, and then the installed software at the users end.
Why not change the ACP and XF site, so that mods are uploaded in an app basis, which my understanding is simply a self install bundle... some simple XML installation instructions in one file telling the app to install. The user already has their forum URL, etc, entered, so it would install obviously based on the users already entered details.
How nice would it be, to simply go into your ACP, view an install page that talks with the xenforo.com site, providing a quick, clickable, list of all apps (mods) available for the version installed, click a link and it downloads from xenforo to the user server and installs itself!
Fantasy or possibility?
Everything about Xenforo is innovative, except modifications, which mimic decade old, and longer, thinking. The new world is app installation... click and go, ease of use... everything XF is, except when it comes to mod installation and control of mods, here at XF. Yes... I am aware you are already in development of cleaning up and enhancing a mod repository here.
Again, fantasy or possibility for the future of XF?