We will definitely cover how to use third-party packages, including using Service wrappers and other ways to “make them native.” Doctrine actually replicates a lot of functionality of the framework, so I don’t know that it makes a lot of sense to go in-depth on. Basically once you’ve loaded it you are using it as an alternative layer to the framework’s database-model-entity trio.
If there’s a lot of ORM demand I could see a section covering how one might approach this functionality, either in the playground or the User Guide.