EDN is natively extensible to more types, for example, the dozens of types postgres supports which actually makes EDN significantly more suitable for this use case. JSON can't encode the difference between a string, a date, a timestamp, and a uuid -- they're all encoded as strings and consuming code needs to go out of band to understand the type.
the stuff about EDN being natively supported by clojure is a red herring and irrelevant.
It is not a small wish to ask them to take on supporting a serialisation format. They will need to integrate it into the core code and it will need to be supported indefinitely.
I asked because I wanted to know if there was a particular reason for your wishes -- which is, as I said, quite parochial compared to the reach of JSON -- over other potential priorities. If asking questions is "trolling", I'll be over here with 4chan and Socrates.