It's also quite rare that someone of Confederate heritage is placed in a hero-type role in a series.
I haven't seen it beyond the pilot, but they were at great pains to make his character highly respectful of black people as equals in a way that was anachronistic for anyone other than the most radical abolitionists of the time - Frederick Douglass and John Brown believed in equality of the races, but it was a very unusual opinion, and for a Confederate...? Well, given that we're talking about millions of people, I guess there could be
one.

The World's Only Abolitionist Confederate!!! No wonder he's special enough to be the focus of a TV show.
But it sure looked like a chickenshit whitewash to me. They didn't want to take the risk of making the guy as racist as any white guy, Northern or Southern, would have been, for fear the audience would have bailed.
Yet
Deadwood never stooped to anachronisms to avoid an audience backlash. They threw a character named Nigger General at us, and dared us to change the channel (and that wasn't the only offensive thing they did.) That kind of guts, I respect. Just be honest and let the chips fall where they may.
As for Mal, he was a general rebel-type. We didn't know what exactly he was rebelling against, and indications were, it was something we could sympathize with. He wasn't trying to defend an unjust system, like the Confederates. Rebel characters are very popular in fiction overall.
The bizarro way the Civil War has been portrayed in fiction (particularly in movies and TV shows) is an entirely different topic. Someday, I'd love to see someone with the sheer guts to tell the truth: the Confederates truly believed they were in the right, because they believed black people were property, not humans.
Say the government comes along and tells you that you're not supposed to own mules, and that you've never had the right to own mules, and you're a bad person for owning mules, and we're going to take your mules by force. WTF!!! What kind of government does that? An oppressive one, of course. That's how the Confederates saw things.
Their viewpoint doesn't play so well today because they were factually wrong in their premise that black people are like mules, not people. But without acknowledging that as their premise, their behavior makes no sense to modern people, so we get BS inventions like "the Civil War wasn't about slavery." The Confederates themselves went on and on about how it
was about slavery, and that slavery was a
good thing, for white people and black people. I've read copious first-person accounts from the time reiterating this view.
In that context, our Abolitionist Confederate hero is a very odd duck, indeed. And in making him so anachronistic, the writers have given up the opportunity to tell a more truthful and possibly interesting story.
The Confederates who didn't believe that blacks were human, weren't all monsters, you know. They could believe things like, it was good to be a kind and humane master, that they were being paternal and protective of their slaves, that being a slaveowner was a bit of a burden, but one that they were willing to bear. Why not write the character truthfully and rely on the intelligence of a cable audience not to run away in horror? We can take it.
Anyway, what I came here to say:
NBC has passed on The Frontier. Rats!