Takes a bunch of manual work per POD, that's the gist of it.

Fundamentally, if I have struct { int x = 3; std::string y = "bla"; }

I want the json to look like { x: 3, y: "bla" } without writing any code specific to the struct, and have it work bidirectionally. This is currently not possible because of a lot of reasons, but most trivially because the names "x" and "y" do not even exist anymore in your compiled code.