Huh I never got the sense the Rakasha are THAT monster like. Cool mental image tho
Rakshasa one might be a bit much. I mean they still have hair and regular eyes and all that. But their bodies are WAY twisted. They come in 22 different variations and combinations of 1-3 heads and 2-6 legs and arms and some even have sort of trunks on their faces, and they're 5 times a human size and completely insane. I think the level of monstrosity is quite accurate even if the degree of insectoid is a little too much.
It's not in the description, but I do see them as being a bit chimaeric. The lore says the experiments that birthed them sought ever more lethal forms so it's not crazy to think bits were inspired by various lethal animal forms.
Also, I think in some point that squamous mentioned that Grade-N nanotechne has a particularly Giger-esque motif. So the tech (guns, exo-suits, etc) of Rakshasa, Asura, and Yaksha should be kinda out there on the creepy pseudo-organic side of sci-fi aesthetic.
I'm thinking maybe if the posthumans are slapping extra body parts on themselves, maybe it would make more sense to give them ones that would provide a practical benefit. Why not have some of the more powerful ones have sort of a centaur like lower body, for extra running speed. Or maybe... I dunno, that's really the only one I can think of. I mean, if you're able to customize your own body, imagine all the crazy things you might try.
Some of the Rakshasa do have warped centaurian (or even hexapedal) bodies. The Asuran progenitors (Anti-nirvanists) took obvious Vedic inspiration in the design of their new forms and chose forms that mimicked both the eponymous Asura and divine figures like Durga to mark their ascension to demi-godhood and immortality. The design choices were out of vanity and not pragmatism. At least, that's my take on it.
A race of pragmatic, heavily-augmented cyborgs could be cool. They could each augment their bodies with different sensors, tools, and appendages that would allow them to optimize their performance in their specific professions. Their entire civ could be dedicated to salvaging as much knowledge and tech from the Old Earth as they can find and then safe-guarding it against any further loss. To ensure future generations do not lose sight o this purpose they would also worship technology and knowledge, their priesthood doubles as their scholars. Because they seek to recover all the past, they revere the ancient and speak only in Latin (or a messed-up Latin that is the best they can reconstruct). And they also like to wear full-body red robes just 'cuz.
It would be cool, but I guess it's been done.