I'm in the early stages of developing a substance painter plugin using 11.03 that tries to duplicate a reference texture with the asset directory of the user. It looks like the API's able to create a layer, but it doesn't seem like assigning a .sbsar file to a layer. I can't seem to populate a resource of any kind to a newly created layer. Implementing this feature could make for some really cool processes. And with the future of the API in mind, it'd be nice if the API could also adjust the color of materials, roughness, if they have normal maps, etc. I think the more I can do with the API the more fleshed out we can develop.
Forgive me if this is already a feature, but I can't seem to find this ability anywhere.