There are also some concerns beyond the ones you listed above. One such fairly fundamental concern was raised by @Langlaeufer earlier in another thread.
I’d also argue that the counterexamples of living_street, etc do not really apply here. At least in Finland, the value of e.g. living_street follows primarily from traffic_sign=FI:E24 and encodes multiple restrictions enshrined in law. Similar considerations, though mutatis mutandis of course, apply to restaurants vs cafes. In most cases an unambiguous decision between amenity=restaurant and amenity=cafe can be made just by looking at the name of the establishment.
I’d argue that at least some of the vagueness in the use of the path tag is due to the vagueness inherent in the paths themselves. In my humble opinion the best way to deal with this would be to use the descriptive tags, whose values exist on a gradation, and thus allows one to express the vagueness directly.
This is of course not to suggest that none of the backlash for new highway values might be due to people like me just being the fogies and neckbeards of OSM 
.