What losses helped a show?
Examples:
Shirley dropping her accent after the first episode of Laverne and Shirley. Truely fake accent
Mrs. Brown's daughters dropped from My Favorite Martian. Mrs. Brown's character seemed to work better without the daughters
Milton Armitage dropped from Dobie Gillis - Completly superficial.
Ann Marie loosing the bangs, and not to sound sexist, the '50's/'60's styled bras on That Girl. She seemed to have matured in the last season.

What others are there?

I'm not suggesting character replacements even though the Dobie Gillis reference might suggest that. Just looking for people, places, and things removed from a show that made the show better.

when jean stapleton stopped using her real voice in playing edith bunker after the first season of all in the family and switched to using the high pitched funny voice that we all remember the switch made edith go from midly amusing to lol funny:lol:

There's only one that I can think of, pertaining to The Facts Of Life. At the start of season two, they dropped several characters from the first season (mostly teenage girl students who were going to Eastland). And actor John Lawlor, who if I remember had played the principal or vice principal in season one. The writers and producers wisely realized they had too many characters on the show and cut it down to a core group to focus on. That core being Mrs. Garrett, Blair, Natalie, Tootie, and Jo who debuted on the premiere episode of season 2. But I've sometimes wondered how they decided which of the teen girl characters they were keeping on the series, but overall it was a good choice removing so many characters from a half hour sitcom. There was just no way they could've written good stories for all of them.

Ed.

when jean stapleton stopped using her real voice in playing edith bunker after the first season of all in the family and switched to using the high pitched funny voice that we all remember the switch made edith go from midly amusing to lol funny:lol:

That reminds me how Megan Mullally spoke (https://www.nickiswift.com/91170/celebs-sound-much-different-real-life/) with her natural voice (https://www.tiktok.com/@willandgracetvshow/video/6934914751956831489?lang=en) in the pilot for Will & Grace and then decided to speak with that really high pitched voice (https://www.purewow.com/news/megan-mullally-karen-walker-voice-will-grace) that we know from her Karen Walker (https://www.reddit.com/r/WillAndGrace/comments/77pqtv/karens_voice/) character going forward.

One Day At A Time made the right choice changing the married with a wife downstairs hitting on every woman in the building Schneider in the pilot to a divorced man who became surrogate father to the girls and close friend to Ann (albeit an annoying one at times, but hey, it is a sitcom after all. The passkey bit didn’t age well, but :shrug: , back then I guess they thought it was funny)