If wonder woman hits big, as I suspect it will, I would not be suprised to see a sequel to Serenity in theaters, and Joss being able to write his own ticket. As he has said, he figured out what he did wrong with the film, and that was he didn't give them anything to market.
Although personally I would have hit the market with a fun, but VERY action heavy trailer, they tried to show the humor, and the fact is his humor doesn't work out of context.
Really, How come? I figured they'd cast someone very popular, or very up and coming, in the lead role and I expect the studio to advertise the living crap out of this one. And with that combination I think they will have a winner, because Joss is a decent writer so the film shouldn't suck high volume advertising and good word of mouth usually equal success.
I would love to see Firefly back on TV, but I liked the film a lot more than the show, so I could handle another film.
I also would not mind seeing Joss create somehting wholly original for his next film.