would there be interest enough to warrant bringing them up to Warband level?
IIRC, I looked at this stuff for the Celtic gear sets, largely looking for some "civilian" or low-level clothing for bandits and the like.
The main issue with the pack is actually naming conventions; everything needs to be renamed. You cannot just call stuff "byrnie" or whatnot; it causes all sorts of issues in mods that have combined a lot of OSP stuff.
So, using "ad_" for AlphaDelta, it'd be ad_nameofmesh, ad_nameofmaterial, ad_nameoftexture, etc., so that it can just be dragged and dropped into a mod without causing needless name collisions and other issues. That would really improve the pack.
The BRFs also needed working bump and spec maps and LODs, as you've indicated, and a lot of the meshes are pretty low-poly, even too much so for Warband. That could be fixed- they just need a few more loops along the arms and legs, mainly, to round them out. You can use Wings to do that non-destructively; if you don't push / pull the points around a lot, it won't damage the UV map or cause much stretching, in most cases.
I've run into these issues a lot in OSP packs; fixing most of this is not too hard, just time-consuming