What shows had characters that changed dramatically (or somewhat dramatically) during its run. I don't mean like puberty or a baby going from being a baby one year to a 4 yr old the next.

Darlene on Roseanne went from being a funny, smart ass kid to the depressed goth chick, to I'm not sure what because I quit watching.

Willow changed a lot. Wesley changed even more, IMO. His character arc was probably the most interesting of any of the Buffyverse characters.

David banner in "The Incredible Hulk".

Wesley from Buffy/Angel, hands down. Bumbling shy guy, to locking women in closets. Good stuff.

Banner. Hehe.

Damnit, two mentions for Wesley already!

Ellen

Frasier Crane on Cheers changed more than any character I can think of, and then changed (back) again once he moved to Seattle.

Sipowicz (sp) on NYPD Blue - but the series was kinda about the redemption of Andy.

McNulty on the Wire.


Then the pussification of Tommy Gavin on Rescue Me this season whatever that is about.

That is why I never liked the sitcom Frasier, because the way they changed his character back into what he was like at the beginning. To me it did not make sense

This one goes back a while, but the Lou Grant character changed quite a bit when he moved from The Mary Tyler Moore Show to his own Lou Grant. In some ways, you could say that he was the same character in name only.

The Fonze - from a non-speaking, blue jacketed tough guy, to a leather jacketed song and dance man.

Peg and Al Bundy - they actually seemed to like each other in early episodes, but turned into cartoonish charicatures by the end of the series.

Bright Abbott, from womanizing jock to sensitive Ephraim clone.

I've noticed that as well as I watch the seasons again as the DVDs are released (F**k Sony is taking their time). The Season One episode, "Sixteen Years and What Do You Get" is the perfect example of this. By the end of the episode they ended up dancing together & showing their love for each other in the typical "sitcom sensitivity" way. Then as the episodes roll along you see less & less of their love for each other & more & more of their hate for each other. If someone watched the first season & then jumped to the fourth or fifth, they wouldn't be watching the same Al & Peg. Now I'm not saying it was a bad thing that they didn't show the whole "I love you" thing to each other but by the final season (11) they were just (like you said) cartoon characters.

Also, Peg's make-up (look) style changed. Al always looked about the same though.

Alan Alda's Hawkeye changed dramatically (literally), but for the better on M*A*S*H.

The cast of Seinfeld weren't complete a**holes in the first 2 or 3 seasons. Julia LD. wasn't as grating as she would be in later seasons.

Elliot Reid (played by the one & only Sarah Chalke ) on Scrubs went from the "natural" look to the "sluttier" look.

One of the bigger changes in a TV character (also from MASH) was Margaret "Hot Lips" Houlihan. She was having an affair with a married man, was very pro-war and was always on a power trip. Her nurses hated her and so did everyone else in the 4077th. Simply put, she was a bitch.

Then one episode she comes back from Tokyo engaged to Penobscott and right away you start to see that she's opened up a bit more and is a bit more fun loving even if she was still pro-war. After Burns left the show and she got divorced she was suddenly "one of the guys", playing along in some of their schemes and her nurses liked her (especially after an episode where she confronted them about not being one of the girls). She actually cared about other people, stopped the power-tripping and it was hard to get a grasp on her stance on the war (she seemed to still be of the military mindset, but she definitely wasn't as gung-ho about the war as she used to be).

It almost felt like they killed off the Hotlips character (did anyone even call her "Hotlips" the last few seasons?) and replaced her.

Kramer changed alot.

Does Trapper John from MASH count from the MASH series to Trapper John MD?

Waylan Smithers appeared to be black in the early episodes of the Simpsons.

Kelly from The Office.

Mr. Garrison got a sex change on South Park.

Michael on Melrose Place. From a good doctor and husband to a lying and cheating a-hole.

Another for M*A*S*H:

Klinger. From cross-dressing Section 8-seeker to clean-cut corporal.

Archie Bunker changed big time.

Scully went from being the skeptic to the one with the zany theories in the last few seasons of X-Files.

Gabrielle from Xena Warrior Princess

Londo Mollari
G'Kar

Yeah, I can't believe I forgot abot Hotlips. But I think most of the characters on that show changed a good bit, assuming they didn't leave. And generally, those changes were not for the betterment of the show.