Some additional comments:
Ideally, I want to see all the grafting rules from every supplement updated and harmonized with lifeshaping, and the otherwise horribly written Manipulate Form fixed and included too.
I kinda see an ability on the level of (a fixed) Manipulate Form as to how ancient lifeshapers did the complex and powerful lifeshaping… and why a womb was required - they needed extra organs and biology to pull off the trick. It definitely needs to have the TO recursive aspect explicitly removed at least… and in my mind add the limitations with grafts to the ability.
Possibly split lifeshaping into minor, medium, and major (or more) groupings, with scaling requirements for each grouping, along with suggestions for degrees of inclusion in each setting. This would allow player access to grafts, in line with other sources, without allowing access to most lifeshaping within Athas… and providing a full set of lifeshaping rules for DMs to use as they see fit in any campaign.
Actually, now that I mention it, I think all the Athas rules and monsters should include suggestions and modifications necessary for use in all of the other settings, by default.
While part of the point is to make it all Dark Sun 3.x, I think we should keep an eye towards making fun and useful rules that DMs in other settings and Primes still want to use, even people not playing D&D will find useful!