Like Star Wars, Firefly revolved around a single, dominant, epic conflict.
Not really. The war between the Browncoats and the Alliance was
over.
Firefly was not about the war, it was about people who had lost the war and how they built a meaningful life in spite of losing everything. It's a story about the people history stepped on, not a show about a Grand Epic War For Freedom™
.
It depends on who wrote the history books -- perhaps they wanted rid of the "undesirable elements" and sent them away to colonise another stellar system, using the blue hands to control them from a distance.
I don't really see how turning the show into an
X-Files pastiche--"People from a culture and planet we have almost no connection to are controlling our society secretly"--really has anything to do with the narrative themes Whedon used or intended to use
Firefly to explore (center/periphery conflict, corporatism, cultural syncretism, economic inequality, etc.).
ETA:
Do you all remember that single scene in the pilot episode when the crew is threatened by the Reavers and Inara pulls out a case with a syringe in it? Well.. as with most things Whedon he didn't do it just to do it or fill the episode. In a story that was planned this syringe contained a drug that a Companion could take if she expected to be raped and it would kill the rapist after the act. One episode would have the Reavers kidnap Inara and when the crew got her back they would encounter the Reavers ship with all Reavers dead and only Inara alive on board.. think about that for a moment

Yeah, I think that would have been a profound misstep, especially for an avowed feminist like Whedon. Rape is used far too often as a dramatic trope for female characters.
I adore Buffy and Angel but they were mostly pop culture shows.. there was drama but it was comparably light drama. Firefly was much darker than any Whedon show
I really don't know how you can say that, given the existence of episodes like "The Body" (
Buffy Season Five) or "A Hole in the World" (
Angel season five).