This proposal seriously hasn't been thought-out well enough. Not all legwear are just socks, thighhighs, and pantyhose. There are things like knee braces, leg warmers, detached leggings, etc. Are we planning on giving all these kinds of things their own color tags as well?
Also why is stirrup_legwear on this list? Do we seriously have to make separate stirrup_socks, stirrup_thighhighs, stirrup_leggings tags? The same for fishnet_legwear, ribbed_legwear, lace-trimmed_legwear, frilled_legwear, torn_legwear, etc. It's absurd to deprecate these things in favor of <trait>_<specific garment> tags when there can be so many possible kinds of garments to have to replicate an individual tag for to cover the same damn concept.
Even if you bring back your <trait>_<garment> tags, the broader <trait>_legwear tags would still be needed.
These tags serve as either essential parent tags or as mid-tier organizational tags. Stirrup legwear for example is an essential parent tag for the stirrup feature that legwear can have. Deprecating it would be the same as deprecating the cleavage cutout tag to force all tags to have to be cleavage cut dress, cleavage cut shirt, cleavage cutout swimsuit, etc. fishnet legwear for example can be a useful organizational tag, as they account for over 2/3rds of the fishnets tag. If a user wants to see what other kinds of things that can feature fishnets that are not legwear, without the fishnet legwear tag they'll have to start adding additional -tags to their searches.
The main thing here is to undo the sock, pantyhose, and thighhigh color merger, because those are completely different things. I don't think anyone searching for black pantyhose actually wants to see black socks in their search. The rest can be worked out.
And I don't think we need umbrella tags for legwear colors. Just like we don't have umbrella tags for elbow gloves and detached sleeves and bridal gauntlets. Just because they're all worn on the same body part doesn't mean we need an umbrella tag for them. Tags like black legwear are too broad, they lump everything from ankle socks to pantyhose together under the same search.
There's a false economy in tagging here. It's like lumping white panties and white bra together into white underwear because it saves two whole tags, then cramming other things in there too, like bloomers and sports bras and garter belts. Then we pat ourselves on the back for how many tags we saved, meanwhile nobody actually wants white bloomers to be lumped into their white panties search, or to have some uselessly broad white underwear umbrella tag.