Dun dun dunnnn!
Cons:
I will say, I thought giving William a cheery, jokey bff in the army was a little transparent. The second this dude opened his mouth I was like "ah, he's about to die so William can learn the true horrors of war." I didn't dislike everything with William in this plot thread, but it's probably the least I've cared about adult William since we met him; he's more interesting to me as he relates to the interpersonal connections of Jamie, Claire, and Lord John. Big surprise there.
I feel like they made Rob Cameron just a little too pushy and sinister? In the books I think there was just a little more time to get to know him as a purely innocuous figure, so here it's like we barely know him and now he's pushing in for dinner invitations and asking questions about Roger's papers, like... it's pretty obvious pretty quickly that something's up. I don't know how I would have solved for this, but just thought I'd mention it. The pacing also kinda made the Buck thing a little less impactful, just because we go from "what the hell are you doing here" to "I forgive him, he's Cousin Buck" so immediately. It also made me miss Roger having a huge scar on his neck and difficulty speaking clearly. That's such an important character trait for him in the books, that he never fully recovers from his near death by hanging. I get why for practical reasons they cut it out, but I think it makes his relationship with his ancestor more compelling if the evidence of his close call is still there in every word he speaks.