To risk oversimplifying things and taking a step too far backward, I see the debate as just a common facet of fandom and interpretation of fiction. When a large group of people are presented with a character who is complicated at best, we're bound to see extreme differences of opinion and interpretations, so I've ignored most of the discussion assuming it was the same thing I've seen several times in other places.
As for my opinion on him, I found him honestly very forgettable. I never had a strong opinion on him and am surprised to find that I'm somewhat alone on that. As I believe I've said before, I don't think this is a fault of Brandon's writing.
The way I see it, Moash is a character foil created specifically to explore and define Kaladin's character (and other facets of the story, if less directly), and because of that I never really gave him much thought beyond comparison to Kaladin. Moash's political extremism in RoW, his acceptance of Odium, even the way he provokes Kaladin's mental health issues are all ways to contrast Kaladin and add to Kaladin's arc. Moash is the version of Kaladin who gave into anger, depression, apathy, etc.
I always felt like he's not really a character written to get the audience to feel something, but is instead written to aid the character who does make the audience feel something (again, Kaladin). I never felt like he was written to be likable or hate-able, he's just there--and maybe that's why interpretations vary so much.
Even without Kaladin as part of the discussion, on a larger narrative level it just makes sense to have a character like this. Often when portraying different moral standpoints and asking questions of morality as part of the narrative, you want to make sure you include characters who fall into a wide range of moral standpoints so that you can explore different perspectives and outcomes. We have several redemption arc characters within this story, so it only makes sense to also have a corruption arc to balance things out. That's not to say it'd be poor writing to redeem him, it shouldn't matter what his fate is because the corruption side of things has already been represented 'on-screen.'
He's a narrative tool. A parallel, a foil, etc. Nothing more to me, personally. If he get's a redemption arc, I think that's cool. If he dies a horrible death I won't cry.
My personal opinion on what should happen to him? He should be treated with mercy because everyone deserves that, but he should also see the consequences of his actions. If he does have a redemption arc, he should spend his time trying to fix what he's broken. However, that's just my real-world moral standpoint. If a different outcome serves the narrative better, then it serves the narrative better.
What do I think Brandon is going to do with him? I think either paths would work, though a redemption makes more sense to me for the story's overall themes. I could honestly see it going both ways, though.