Having re-watched 30 Rock several times, it really stands out how much Jenna Maroney improves throughout the series. She is a one-note, generally uninteresting character in Season 1 and part of Season 2, to the point where she’s barely mentioned in some episodes. She really doesn’t have any significant stories for a long time. Eventually, as her character’s career starts to take off, the show ramps her absurd character traits up to 11. By the end of the show, she goes from a side character to one of the most important parts of the show, hitting the emotional climax in the finale. She is a funhouse-mirror reflection of the Season 1 character and as Flanderized as any character on TV.
And it works. She is more fun, interesting, and ironically also developed and deeper. Most of the characters are Flanderized a little, but none develop as much as Jenna. Tracy is definitely a different character, but he was always ridiculous, while most of the rest of the cast are varying degrees of the same.
I don’t know if I can think of a show that really pull this off so well. A lot of shows change or develop the characters as they progress, but the examples of good Flanderization are few and far between. You could probably make a case for Winston on New Girl.
Are there other good examples?
I’d add both Winston and Schmidt from New Girl.
Obviously Ned Flanders has to be on the list too.