First of all - thanks for the link, it actually pointed me to another thing I needed to solve
Regarding the new APIs - it seems to be going in a good direction, in particular this part
// Create a DatastoreParameters object and report a call to an external datastore service
is almost exactly the data I expect to be able to tell New Relic. Having said that, this code is explicitly reporting the call as “external” which sounds like quite the hack.
I will give it a shot later on after I upgrade to the latest agent/API.