Actually, I believe you can in DS, but it needs to be a DS script. Problem is that some users are still using DS2 and DS4 is in alpha. A script written for DS3 won't work with either. Added morph channels are a better solution for DS. Yes, there could be some overlap, but the chances that a user is going to use all 10 of those hypothetical sets of 10 morphs each at the same time are fairly slim.

As for DS compatibility, as a DS user, I do appreciate those who are considerate enough to make things work for us too. No, not everything for Poser works in DS, but at least some level of compatibility is nice. Changing MAT poses to .pz2 gives DS users a starting point for MATS even if you're unwilling to create DS MATS for them, and not using PMD morphs insures that users will be able to use them as easily as Poser users or in some cases at all.

V4's DS dynamic clothes work fine on Antonia, so dynamic clothing isn't an issue.

Really, the only places for real compatibility concern are morphs and MATS.