You mentioned problems with gRPC, but I think every one of your problems is with protobuf. Is that correct?

Also, regarding point 3, I'm confused with two things:

- You want "free form" data, but you're talking about protos in the context of Go. How would you define this "free form" data in Go?

- You explain that "free form structured data is important for systems that accept foreign data ... where the schema isnt known". Why are you using protobufs for this usecase? Protobufs are specifically meant to make the schema known, and be enforced by serialization.