It would be brilliant, but it isn't realistic at the moment. I don't think anyone would want to watch Firefly without Mal and Jayne, and those actors are both under contract (to Castle and Chuck, respectively).
I've said before, and I'll say again -- those cast members are crucial to what we think of as Firefly, but in reality, it was Joss Whedon who put it all together.
I can't imagine how great it would be to get the original cast and crew back together to continue work on Firefly, but in reality, anything that Joss Whedon considers good enough is likely good enough for me, whether or not it's a spin-off, new series or what have you.
I respectfully disagree. This isn't to say that I don't fully appreciate the brilliance exhibited by both of those actors (especially seeing how mediocre Baldwin is in almost everything else I've seen) in those roles, but Joss Whedon does two things really well -- write compelling dialog, and make exceptionally good cast choices.
I do consider Firefly to be Whedon's magnum opus, but you can keep the concept without those two actors, or without any of the original cast really, but there's nobody you could cut that wouldn't be sorely missed. The real question is whether or not it's still 'Firefly' or a spinoff. And, my take on that is to accept whatever Joss Whedon says. If he calls it Firefly, so will I.
That's probably an expansion path being considered. There are plenty of series that have had big cult success after their cancellation. Firefly is one of them but there's also Arrested Development and, more recently, Better Off Ted for example. Letting others take the risk and capitalizing after proven market viability (basically picking up half of what Fox cancels) could be interesting.
Yeah, the last few episodes of Sarah Connor Chronicles were really exciting. The last episode is a twister, and you really want to know what happens next in the story.
Disclosure: I never saw Terminator 4, so my knowledge of the series is not complete. I'm told that I'm one of the lucky ones, though. :-)
FYI, it supposedly fell somewhere between the T2 & T3 movies in the timeline. Mostly good episodes with the story picking up (and frankly getting crazier in a good way) by the second season.
It's worth a watch if you can handle knowing you won't get all the answers due to its cancellation.
I canceled my Netflix subscription, but I promise to resubscribe at any feasible commercial price and get another 10 new subscribers as well if we could only restart Firefly (under the condition that it's under the creative control of Whedon)
While there at it buy Stargate Universe, say what you want about the show but some of the recent eps have been excellent, after the viewers have abandoned it due to some of the first season pacing. Add to that SyFy really losing favor with scifi fans and the move to digital as most of the core audience would be internet savvy.
BUY FIREFLY AND MAKE NEW EPISODES.
I would gladly play an extra $4 a month (or more) on top of streaming just for access to new weekly/biweekly episodes of that.