While I agree that it portrays slaneesh as weird non catholic sex too often there arn't many ways to really portray slaaneshi demons besides weird sex demon, weird fat demon or prince sigvald the magnificent and have it be clear it's a slaaneshi demon. Also the closest you can get to showing sex as an obsession at slaanesh's level is an orgy, anything more and you're just asking an artist/writer/game dev to write/make wierd orgy torture porn.

You could make them more of a muddle but they'd be hard to differentiate from just regular old demons.

The androgeny thing idk, it is pretty sus but trying to see it from the viewpoint of a weird god of perfection I can see how you'd be so desperate to be perfect you start yanking pieces from every body type to create your perfection. Still pretty sus tho.

Though this is pretty much solely from my experience of warhammer fantasy and the whtw series. Idk how well 40k handles it in the books.