I could see Don and Megan still working together many years after they’ve divorced and are both remarried. (Don would probably be the type to marry a ridiculously young woman and have kids in his sixties and seventies.)
Most of the characters who have been written out I don’t care about (e.g. Duck) or even remember their names (e.g. “snobby beard guy with the black girlfriend who got fed up with him”) but I wonder if we’ll ever find out what happened to Sal Romano. They don’t have to bring him back, just mention in passing that he now directs commercials/has a drag act/has three kids with his wife/got arrested for stalking Davy Jones/whatever.
I always the it would be funny to have him show up for a once scene cameo where Peggy’s interviewing him for a job.
A sixtysomething Peggy shows up for work early, walking past a sign with the name “Olsen” prominently displayed. As she sits down at her desking drinking Startucks she starts to check her email, then get’s up to look out the window at something…
…cue a shot of the World Trade Center towers standing proudly, yet ominously. Fade to black.