A few quick things I thought of while using ASP the other day:
Perspective Guides
I was using the perspective guides last week.. really powerful feature!! I hadn't seen them before, I would say it would be nice to edit the perspective guides while creating them (like picking their color/thickness).
Brush Creation
I scoped out the procreate beta and I have to say, I think ASP does a much better job with Abr imports.. and honestly the brush engine in general, to me, feels way better in Art Studio than procreate, so cheers! I do like procreate's brush studio in the way you can kind of mess with a brush and see changes on a scratch pad to the right. Makes brush creation a bit easier.
Color harmony
I know I've said it before but it would be really nice to have color harmonies / gamut lock for the color palette.
Freeform Guides/rulers
I'm not exactly sure how to explain this, but I really love the way Clip Studio uses their rulers. Rulers is sort of a misnomer because they really aren't used for measuring. They allow you to 'lock' your brush to a path.. it's super useful when free handing long sweeping curves or ellipses etc.
Honestly I kind of feel bad even suggesting things because this is such a powerful program. Thanks for all your work!
