I'm working on a third party installer for installing web applications on cpanel, get in touch at my email on profile.
(This isn't for cpanel addons, it's for installing packaged applications directly to a user's cpanel-based hosting account.)
It would be PHP-based and might work as an installer, user just needs their control panel login username/password from their webhost. (Too bad cpanel doesn't do oauth2). I've already tested with some of the major web hosting providers.
"Joe Sixpack" isn't using this software. This is a self-hosted project management tool. "Joe Sixpack' isn't in this equation. They call a pro. By your logic, WordPress is challenging to install without Softaculous, and even hard to understand by "Joe Sixpack" with Softaculous. Keep it in perspective of who this is for.