And I risk saying that perhaps media that become iconic shouldn't be touched no matter what happened during production or screening. Because if you start fiddling around it even in a good faith that charm may be gone forever.
"Firefly/Serenity" for me is from same shelf as DS9 or rebooted BSG - a closed story that doesn't need any continuation. These titles got rather bitter than sweet ending; there are questions and that's good. Not everything has to be wrapped up with a picturesque idyllic scenery, where everyone "lived happily ever after".
But at the same time, I don't mind if they roll animated "Firefly". And I give them my thumbs up, will be happy if they manage to success but I don't have big expectations either.