I seem to recall (without specific details) that a number of episodes almost let Frank Burns have a redeeming moment and then he self-sabotages at the very end. At times it very much seems like the writers are the cruelest ones of all.
I think it worked okay. They gave her a lot of opportunity for character growth and showed reasons for her flaws.
Major Winchester ended up being one of my favorite characters because of his redemptive arc. Not because HE is redeemed, but because the audience’s opinion of him is. All of his good qualities were there the whole time - they were just revealed very slowly. He was never a villain at all. Just a decent man thrust into a horrible situation.