I understood that part in the game to show how he was already beginning to fall even before he went to Northrend and picked up Frostmourne. I was pressing the buttons that killed those digital Stratholmians, but I also knew that I was just advancing the plot of a story, even if I didn't approve of the action. If the same scene appears in the Caverns of Time however, then this is not, in my mind, merely advancing the plot. This is my character taking part in activities that I myself would never condone. Slaughtering almost-but-not-yet-undead families feels a little too close to home to me. "They're doomed anyway so might as well slash them to ribbons?" That inhuman attitude is sometimes used in real life to do horrible things, and it's quite chilling.
Well, Blizzard CM Bornakk would disagree with me: "Slaughtering is a strong word," he says, "maybe it would be better to say that you are aiding the pround Prince Arthas in Straholme [sic] as he uses his divine Paladin powers to purify the streets of vile evil undead creatures ... and burns down houses." Well, I'm glad not to be hacking defenseless mothers, fathers and children apart myself, but burning down their homes is a serious thing, particularly if the houses to be burned are supposed to have these not-yet-undead families inside of them. For Arthas to do that in the story of his corruption is one thing, but for my character to help him is totally different.
Now, admittedly you could argue that one of the existing CoT instances has us helping Medivh open a portal for orcs to come and rampage lots and lots of people, and yes technically that's an evil thing to do. But there's a big step between opening fantasy portals and burning down houses that are supposed to have families inside them. Does anyone else see a problem here?
[Also, as a side note, the thread in which Bornakk tells us that slaughtering is a strong word actually begins with a really funny idea for another CoT instance, "Back to the Future," which is worth checking out.]