Some of the userscripts could, longer-term, be converted into server-side Web UI features; I think that that'd make them available to a wider audience, since they become available to all browsers without user effort then. However, for any that don't, I also imagine that it'd also be possible to set up some sort of automated regression testing using Selenium or something like that that warns if it looks like they aren't working in a new version. That'd take load off human userscript maintainers if the userscripts are going to be around for the long haul, and it'd give a heads-up earlier, potentially as soon as the breaking commit goes into git.