The weak spots in the show are the ever-randy weenie, Howard (Simon Helberg), and the Indian guy who can’t talk when a woman is present, Rajnesh (Kunal Nayyar). These are throwaway characters that Lorre himself treats with contempt when he writes the scripts.
I disagree with with Card about the alleged contempt that Lorre treats Rajnesh (Howard is pretty contemptable, though), but I very much agree with Card about the proper role for these characters. They’re indicative of something that I’ve noticed as I’ve been pouring through a lot of old television shows with my Bluetooth and Pocket PC. Some characters — even good ones — are meant to be temporary. It seems that few sitcom writers seem to realize this.
Somewhere around season six or so of Just Shoot Me, the producers wanted to add an actress (Rena Sofer) to the cast and more-or-less forced the writers to come up with a character for her (Vicki Costa). to make room for her they more-or-less abandoned a regular guest character named Kevin Liotta who had become really popular. The audiences hated the new character and Costa was dropped from the show after half a season and Liotta came back for more regular appearances towards the end.
Costa was a pretty awful character. The writers never seemed to get a good idea of what to do with her and it showed. But what I found interesting was that Kevin was a lot less interesting when he came back. In retrospect I think that dropping him (at least to more irregular appearances) was a good thing. In fact, I think that dropped characters, even ones that aren’t necessarily bad ones, can be a good idea. Shows, however, are pretty reluctant to ever do it. That’s a shame, though, because cast changes can really reinvigorate a show. Cast additions, which they usually try instead, can also help… but sometimes you need to create room by subtraction.
I recently finished watching the TV show Becker all the way through. In the first season a character named Bob was introduced. Bob was a loser in high school that had made good and felt that his success should have made Reggie, a former model who landed as the proprietor of a crummy diner, feel regret over rejecting him. He was a good character. For half a season. The problem is that they kept him around for five well past the point that he was remotely interesting. For the last season they replaced him with another character named Hector (played by Jorge Garcia, who plays Hurley on Lost). I wish they’d added Hector a whole lot sooner.
Another example of a cast change being good for a show was borne of tragedy. When Michael J Fox’s illness became too much for him to handle while doing Spin City, they replaced him with Charlie Sheen. Sheen’s character may have been better than Fox’s or may not have been, but Sheen’s character in the two seasons he was on the show was a lot better than Fox’s was in the last season he was on that show. The show had started to become stale and Sheen brought new life into it. Spin City didn’t last but a couple seasons with Sheen, but Sheen did well enough on that show that they gave him a part with virtually the same character on Two and a Half Men.
Speaking of Two and a Half Men, they dropped the character Rose somewhere in the third season or so. Rose was a girl that Charlie Sheen’s character (also named Charlie) slept with who had become obsessed with him. They should have gotten rid of Rose sooner than they did, but at least they got rid of her. They did bring her back for more periodic appearances as a sort of scheming mastermind, but it worked. I think that the break was needed and the lessened frequency of her was a net gain for the character and the show.
There are cases where lost cast members hurt a show, of course. News Radio never recovered from the death of Phil Hartman, Spin City lost more than just Michael J Fox and never were able to replace them, and The Drew Carey Show needed Kate, but I think that had to do with inadequate replacements more than anything else (Does anyone consider Jon Lovitz funny?).
In general, though, I think that shows should have more fluid casts. Most casting changes are done by simple addition or because an actor left or was fired. It’s usually in response to something rather than saying “Hey, this is a good character, we should make room for them” and “This character has run its course, it’s time for something different.” It would be even better if they’d audition characters to see which ones the audience takes a liking to or which ones fit and then use them for a while until the roles have run their part. One example of auditioning working out is Mimi from The Drew Carey Show, who was meant to appear for one episode and instead became a staple for the series.
Overall conservatism is one reason that they likely don’t make cast changes that aren’t absolutely necessary. They’re also probably afraid of losing actors to other shows if they don’t lock them in as a regular. Even so, I’d like to see more experimentation in this regard and less simple reaction.