There's one more thing. The common data model for tracing is great! I captured in my solution the whole request/response head and up to 1-2kb of the body. That helps a lot in error scenarios to see what's going on. Users should be able to access the data model to put some parts to MDC or similar for further investigation.
Added my comments to the doc
It would be amazing to use that sort of capturing within integration tests. The more context data available, the faster a bug can be found.
I have a last thing, that might be also interesting for you
It's remote log capturing during integration tests (that was my use case)
So basically, when you run integration tests against one remote machine (or in a distributed system) and something screws up for instance, you have to grab/correlate logs to the particular use case to see what's up