Once the database can start receiving and returning json, then you can treat it as a webservice and not have the client involved in SQL. I think this is huge.

Just FYI, this is already half-true:

"With PostgreSQL 9.2, query results can be returned as JSON data types."

It also supports the PL/V8 stored procedure format, which is Javascript http://code.google.com/p/plv8js/wiki/PLV8

It's very, very close.

Can you elaborate a little bit on how an architecture like that would look like? I had great hopes for CouchDB once.

HTML/JS frontend calls simple node server that does nothing but call a stored procedure like

   spc_handle_request(req_headers, req_body, http_method, ...)

stored procedure does simple routing and does something like

  insert into table (a, b, c) values (to_json(req_body).a, to_json(req_body).b, to_json(req_body).c);

or

  to_json(select * from emp);

Time to implement simple crud app: 10 minutes.

yet it will not cease comparsions of postgres to mysql