Can't see much success with it.
I'm a die hard fan of Firefly since the beginning but the strength of the show lies with the characters, their interactions, the awesome dialogue and the meta-story.
All this can't translate well to a simple online game (maybe apart from a meta-story but that requires much effort.. something i doubt will be done properly with an untested game). So without these key elements you will basically have a freighter with which you can move around the system, ship goods from a to b and back, maybe have some smuggling and hot pursuit flying against Alliance Police/Military and to spice it up the occasional Reaver attack.
Prepare for an overabundance of "Shiny" and similar catchphrases and oh so clever references to the show and the movie (that will probably repeat itself until you're sick of it).
I'd love to eat my words and that this game proves me wrong by having really unique features, good to brilliant gameplay and something else that let's it stand out. Having seen many MMO's come and go i somehow doubt it.