This sounds like a super interesting approach Adamkl! Do you have something written up about this somewhere?
Our data APIs map from existing SOAP/XML services to small GraphQL sub-sections of our greater API.
Then, we merge those small APIs together with Apollo's graphql-tools, similar to what Airbnb is doing[1].
Now we are starting work on our proxy/processing layers using this[2] work-in-progress.
[1]https://medium.com/airbnb-engineering/reconciling-graphql-an...