But you're arguing that we shouldn't judge people using our modern viewpoints but judge them based on the viewpoints of the time. In your example, there were people who shared the same views as we do now so I don't get how it is an effective example. 
Exactly. Past societies weren't more homogeneous than modern societies. Even in the worst place of the world you'd find people with values that we consider more "modern". People should be careful with historical examples, because they might flanderize entire societies (not that we don't do the same today, sadly).
For example, colonization of the Americas was a grim business. At that point in history people tended to do pretty horrible things to each other, so it's not that they would feel compassion for a bunch of people because they had just conquered them. But there were others, like Bartolomé de las Casas in the Spanish colonies, who pushed for what we would call now 'indigenous rights' (even if the word didn't exist at that time).
Anyway to return to the topic, I think, as someone who hasn't read TME that the section of the game encompassing these characters is going to be fascinating (I think I said something similar in the Gaspard thread) clearly they both are very morally grey characters and I'm looking forwards to seeing this play out, and how my inquisitors will respond to this situation. The fact that they are capable of stirring up this level of moral and social debate suggests to me that they must have been very well-written!
I hope so, but TME was a whole book centered about this issue. Gaspard and Celene had time to shine, and we had insight about their thoughts. However, in DA:I the Orlesian plot will have to compete with other plots and characters. I fear that time contraints may make them more simplistic. Or introduce new elements that weren't in TME and could change their positions. I mean, if one read only The Stolen Throne, they would be surprised to find that Loghain became a villain.