In the survey below, most people see highway=path as a pathway of unknown classification.
This means the only way to tell them apart from “known” classifications is by creating new highway tags. I don’t see how saying only a bare highway=path without additional/specific tags is considered unknown will work.
If highway=path is supposed to function like highway=road, then ideally, routers and renderers would just ignore them, and mappers would get a hint to reclassify them.