Pete as a do-good father and husband? Really? An optimist would surely say he's a changed man after tasting the post-divorce life, but a realist might take a look at the character's entire seven-season history and assume the worst for Wichita. There's considerably more evidence for the latter than the former if you watch the previous six seasons of this show. It wasn't that long ago that Pete was living the life in California with his real estate agent GF, but now we're supposed to believe he won't be tempted by Learjet stewardesses and Hollywood types?
In other, "think about the entire arc of the character" thoughts, Better Draper/Francis lived a truly sad life, which makes her ending that much more tragic. Sure, she was petulant, bratty, naive, and stuck-up at times, but aside from a few flashes with Don or Henry here and there, did she ever really experience love or happiness? Her soft spot for Sally, however, gave the character her humanity, which is why the letter (and her ending) were so emotionally powerful.
I could almost envision the boys ending up with Henry and Sally trailing her father westward.
Weiner wasted so much time on other matters during this broken seventh season that now we're left with just a single episode to conclude the stories of Roger, Joan, Peggy, and Don. I personally would also like to see the futures of Stan and Ted, but sincerely doubt we'll get to see them.