It would be good, if there was an ‘unsupported’ plugin channel where it is clear that these plugins will be installed at your own risk.
That way users who want or need a ceretain plugin that is stuck in the slow vetting process would be able to easily install a plugin without the need to ssh etc.
Also devs could more easily make their plugin available to a larger group and receive faster feedback and test results from users with other hardware onfig then themselves.
In addition the volumio devs could be sure that the plugins that reach the official channel this way have already been tested in the wild, so that would make their lives easier and increase quality of the stable channel overall.