Exactly, one would have a dashboard where one could create and delete instances, also manage everything on the instances, but without having to go to the pages in its settings itself (but which would be possible too, of course)
You would then also have global permissions with which, for example, one can only create instances, delete instances or both!
Users registering in any instance would also be in the dashboard, where they could also register in multiple or all instances! In the dashboard one would also see which user is registered in which instance(s)!
Global bans would also exist so that users could not register and/or log in to specifics or any instance (hosted in the dashboard)
Then maybe a function where one could give users a role with rights, which could then create, delete and manage a certain number of instances with these (handy for resellers 😉)
In addition, the dashboard would be an extra function, which one could install/activate, so that one would not be forced on this hosting function! There would then exist a consumer and hosting version (the latter the one with the dashboard) respectively
Furthermore, one could integrate a plugin management in the core (for both versions, in the hosting one could determine in which instances (or in all) one want to install, update or uninstall which plugins)!