The currently provided public server implementation is suitable for small multiplayer games, but probably wouldn’t scale well to a massively multiplayer game. And Disney’s not going to open-source its OTP server, no matter how nicely you ask, at least not anytime soon. Sorry. We already tried, and got shot down.
But you (and anyone else) are certainly welcome to write a public server for Panda’s use that would scale to massively multiplayer games. 
David