Why not open source the firmware. I think is it GPL right? We should start hacking it to make it a better firmware. Fun_plug is not enough, we need interface too.
Consider fun_plug as a hook - a starting point. It's a way to call whatever script, routine or executable YOU wish to run. Fun_plugs have been written to load an entirely different OS off of the disks - you want to see a different interface, write the code and call it using fun_plug.
And yes, I've created my own fun_plug, and my DNS-323 does what I need it to.