One more experimental but more promising approach:
You can totally use whchever (eg Sonatype OSSHR) Maven repository to deploy to deploy your artifacts (bundles, features...) the pure Maven way (eg `mvn deploy`). Then you can build a p2 repo that references those artifacts from Maven and use the new shiny remap-artifacts-to-m2-repo ( https://wiki.eclipse.org/Tycho/Release_Notes/2.3#A_mojo_to_remap_Maven_artifacts_to_Maven_URLs_in_artifact_repository
) to make your p2 repository just reference Maven artifacts. Then you only have to care about publishing a content.xml/artifact.xml couple; those can for example fit in a GitHub repository.
There are limitations, drawbacks and so on; especially since the remap mojo is only 2-days-old, but it has the potential of greatly simplifying p2 repo hosting as it basically becomes rmuch closer to egular Maven artifacts hosting.