Wow! I really admire what you've done with this scene, because I can too easily see the Operative going off to kill himself, and what would be the good of that? Mal's suggestion that he in some sense follow Book's path and maybe (some day, in the distant future) start to do some of the good that Book did makes so much sense, as does his offer to end it for the Operative in a year's time, if he's still set on death rather than living with what he's done and making his future count for something.

Very well done! And thanks for including that wonderful bit about how you can't atone for the lives you've taken, but neither can you move forward and start to do something better if you're stuck in the past.
That's one thing that I think Spike instinctively understood better than Angel, and why (I suspect) Spike's adjustment to having his soul restored seemed to proceed much more quickly.