For me the show was about the writing and the actors which was all very good. That's stuff that rules don't help with. So, it really depends what is it about the show that made Firefly feel like Firefly to you.
Something like directly giving Plot Points for funny lines would have helped. The combat and wounds systems don't feel like they match up very well. I think its really Cortex, the fiddling with changing dice types makes it feel much mroe complicated than it is.
Of course I feel the same way about any kind of d20 star wars. D6 4 lyfe, baby!