Skeletal would certainly be plainer language. It’s definitely what I was trying to convey, but rictus popped into my head so I went with it.I would tend to think of "rictus grin" as falling on the literary side of things, as does [MENTION=22779]Hussar[/MENTION].
As I've posted, it does no harm if it doesn't impede (what I regard as) the real point of play.
It has a face like a skull might do just as well. I personally can't remember how I've described githyanki in the past - I suspect I'm more likely to have shown a picture, such as the one on the front of the Fiend Folio.
More generally, and feeding this into the current [MENTION=23751]Maxperson[/MENTION] - [MENTION=16814]Ovinomancer[/MENTION] interaction, I think that the role of description in RPGing is easily overestimated. It prioritises immersive imagination orver protagonistic inhabitation. Whereas the latter is the distinctive virtue of RPGs as games that are about producing a shared fiction.
All this said, I think you've fully understood my points in this thread, seem to agree at least to some extent, and have made many helpful posts into it for which I thank you.
I think description is important, but that the amount of description needed is often exaggerated. I’d even say that literary effort can be great for a game, but probably has to be used sparingly or minimally. But I think I’d agree with you about the priority you place on such when compared to inhabitation.