The table approach is fairly flexible. Both Protos and FlatBuffers do more or less functionally similar things. What specific deficiency do you see?

Take a look at the binary format spec:

https://github.com/google/libnop/blob/master/docs/format.md

The format is designed specifically to provide enough structural information that the binary format can be parsed without knowing the original structure definitions. This makes it easy to write a binary-to-string converter than can grok any payload with minimal complexity. Message observability was a primary goal during development.