mobi content_server plugboard

I know Kovid has talked about adding mobi plugboard support to the content_server in the past (circa 2011), is there any reason it hasn't been done since? I hacked on a local copy of calibre and got it up and running with minimal changes and the speed seems more than sufficient (honestly I see no difference in fetch speed with the plugboard on or off for mobi books). At least for a simple plugboard that adds series information to titles.

I'd be happy to contribute the changes, but they are so simple I get the feeling there's a deliberate lack of support.