Well that is why the standards need to start with a portable subset, which may risk not being able to do certain things:
1. Music/sound.
2. Open custom screens.
This basically returns us to the OS3.1 API which is there already, in fact less than that because we are ignoring calls to screens and the like that would tie us to AGA, P96, CGX whatever - so we are basically looking at apps that open on the workbench screen.
Later revisions can tackle common apis for the bits that have to be sliced open. But as a developer you know that if you code for the portable subset, its going to work.
Problem is, how to "open" a proprietry API like AOS? Hmmmmmmmmmmmmmmm.