Speaking of sending Stalins to jail, will Dalinar ever face any consequences for his act of genocide in Rift?
Unfortunately, no. (Other than his strained relationship with Adolin and his own personal guilt.)
Problem here is that by our standards (and now, Dalinar's own) this was a terrible act of destruction. But by the standards of his society, this was just business as usual. A city in open rebellion against the crown? That's basically an invitation.
It's a tricky scene because the awful truth is that in our world, these sorts of things were extremely common in warfare--even up to and including the modern era. It wasn't until very recently that this sort of action was seen as a the war crime that it is.
To be more accurate, I probably should have had this sort of thing happen dozens of times in Dalinar's past. But I felt that wouldn't have made the point any stronger, and felt that one time was bad enough. That said, however, it's not the sort of thing that most rulers through history would have to bear any consequences for.
Has Vasher/Zahel done anything like this? Is that why he is as we see him in the Stormlight Archive?
RAFO for now, but the responses below this do have valid points [Manywar and Nightblood].
Would something like the 1474 trial of Peter von Hagenbach be possible on Roshar? And if yes, would this be something Skybreakers would get behind? It always seemed to be that they'd be interested in the idea of 'make law, not war' (I got that quote from Ben Ferencz).
This sort of thing would have been possible (and indeed inevitable in a situation like that) during the days of the Radiants. Not so much in recent history. Old Skybreakers would have been behind it entirely, new ones have some...different ways of looking at things.