I wonder if GraphQL would make more sense as a client side technology. The goals of dev ease seem better served by a graph the client can build (and thus span multiple remote services). Instead of transforming the backend, you simply get a better UI dev experience and the middleware handles query aggregation.

You'd want code gen to easily wrap REST services.

You could get some of the pipeline query/subquery stuff back (and lose caching) by setting up a proxy running this service or fallback to client side aggregation to span services not backed by the graph system (and maybe keep caching).

Maybe we're back to SOAP and WSDLs, though.