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.
Joey from Friends is way more interesting as a doofus