Somewhere along the line, Matt & Trey made the South Park police for much bigger with a real department lead by that red head cop. I guess they couldn't come up for any more material for the brainless cop and wanted a more stereotypical hard nosed cop.
Yeah, the Little Crime Stoppers episode definitely expanded the south park police and pushed Barbrady aside. Toiler Paper (3 episodes before Little Crime Stoppers) is the last one where I think he had a major role.
They've definitely slowly phased out a lot of the the older, more commonly seen characters. The Mayor, for example, has only had die hippie die as a major role in years....actually, Barbrady might have in in that too. They still show up every once in a while, but with the perfection of the Randy and Butters characters...eh. Nobody should be missing them.
Yeah the red headed detective is much funnier. He's one character I don't miss. Dont' really miss Mrs. Crabtree either. I love how they killed her off. She got killed by a serial killer in one episode and one of the cops said "poor mrs. crabtree. she just wasn't funny anymore so that's why she got killed" or something like that.
Barbrady is only occasionally funny, I don't miss him at all. I especially like the new cop since the episode with Michael Jackson though, where he's freaking out about how he almost hurt a white person.
You might be mixing up the person who did almost all the female voices in seasons 1-2, who killed herself. Which is why Wendy's voice has changed so much, though whoever they got to replace Kyle's mom does a good job sounding the same.
Tweek - one of my personal favorite characters - had a good run as Kenny's replacement (after they turfed Butters). But too much of him can be annoying, even Parker admits this. He still shows up for a line or two every now and again. Or just a twitch.
Barbrady had one of the best lines of the second season:
Well, first of all I'd like to thank the town of South Park, the town that borne me, and eventually will rob me of my life precious. Second, I'd like to say to all those out there who think they can screw chickens just to teach people to read: your days are numbered! And finally, I'd like to say that reading totally sucks ass!
Yes, at first I was happy to be learning how to read, it seemed exciting and magical. But then I read this: Atlas Shrugged, by Ayn Rand. I read every last word of this garbage, and because of this piece of sh*t, I am never reading again!