I think PAC3 integration is a really tight rope to walk. Some communities can act responsibly with it, but you'll always have Some People. By the simple virtue of being an incredibly powerful customization tool, virtually nothing bar experience stops someone from making either an incredibly good, incredibly annoying, or incredibly complex outfit that everyone who sees it will have to download from that point forwards. It might not be harmful to another user's PC, but it might be an assault to the senses and to immersion.
Obviously, that's a user problem and not an addon problem, but can you really trust the community to have that in their hands? Trust is the ultimate factor here, and if you base the system on trustworthiness, you might have a very, very restricted system that ultimately means that very few people will actually enjoy PAC3's additions.
Still, there's something to be said for the things it can add: Physical traits unique to each character, such as lost or disfigured limbs, different body-shapes (within the limits of the player scale), and mild trinkets like a hat, glasses, or something like that come to mind. When you look at PAC3's capabilities within reason, you quickly realize that it opens the door for a myriad of ways for players to express their characters in minute ways that Helix's base systems generally just cannot do.
I don't want to pretend that I know how PAC3's integration with other addons works, nor how its API functions, but a solution I can think of is to whitelist individual outfits instead. I doubt that it's possible in any practical sense and if it were it's probably very easy to circumvent unless the outfit itself has some hash to verify it is what it is, but I like to imagine that some of the customization options I can select on the butchered and modified carcass of an MMORPG are possible on the corpse of a slightly less butchered first-person sandbox game.
