I use JOSM to do my editing, which has a revert changeset functionality. However you need to be careful in using this. Given the small size of the changeset it would be easier to modify each road section (JOSM can retrieve all the ways/nodes etc modified by a changeset, allowing the tagging to be changed easily.)
I was planning on waiting another day or so, than was going to change the highway classification back to the previous classification of secondary, if no consensus was agreed. This is in alignment with other similar roads across the Alpine area (i.e. Mckillops Rd to the south, or Benambra-Corryong Road to the west) and across Australia as noted above.
It is definitely a higher classification than “unclassified”. As noted above it is a part of the arterial network, a heavy vehicle route, and has a ‘C’ route classification in Victoria so would meet the ‘secondary’ guidance on the Australian Tagging Guidelines for the Victorian section. The NSW section could be either ‘tertiary’ or ‘secondary’, however, to me, it makes sense for the full route to be secondary given the description on the wiki.
I’m also planning to adjust the smoothness to align with what was experienced by myself for the Victorian portion of the road, which was majority of the road was intermediate, with the surface smoothness not governing the speed, noting the surface is a mix of paved and unpaved roads. The speed as noted above was governed by the corners and visible distance required to be able to stop especially in narrow sections of the road.