I converted about a dozen (female) wyches to lhamean and I've actually found them pretty handy. All you really have to do is add some kind of skirt to them. I did make sure all mine had pistol/knife/hairpin however.
Haven't figured out how to take good pictures of models yet, but at least I haven't ruined these with an attempt to paint them (so far).
Tactically, I think of them as a lot like taking 1/3rd of a grot - which is about how their damage and cost/wound work out. Using that logic: they excel in low point games, where you don't have the resources to commit to a (second?) grot bomb, or you simply need another venom and decide to pay the HQ tax while you're at it.
So ya they lack armor, but what in our codex doesn't? They also lack grenades,
but as an escort for an HQ this isn't an issue as either choice has grenades
. No combat drugs on these girls is a bit more of an issue, but realistically not much of one.
Ideally I try to use these as a second charging unit, after a more durable unit hits an enemy and soaked up it's overwatch. If I've taken a succubus she gets haywire and an archite glaive, an archon usually just gets a blaster.
So like anything in our dex - you definitely can find a use for it, but it helps if you opponent is unfamiliar with it.