Adding new regulars to a comedy can be tricky. Not dramas; today’s dramas at least, are more or less built to accommodate the coming and going of characters; you expect that they’ll add a regular or two every year and, on some shows like Lost, drop almost as many regulars as they add. But because a comedy is usually based around a relatively small core group, adding a new person to that group is usually taken as a sign of desperation, an admission that something wasn’t working the first time around or that the network is meddling. When a drama adds a new regular in the second season, it’s a normal occurrence; when a comedy adds a new regular, it’s usually because the original cast just didn’t quite cut it. Call it the Steve Urkel Theory of Comedy Casting: any character added as a regular to a comedy is added to make up for some deficiency in the regular cast.
That said, just because adding a new regular is a sign of desperation doesn’t mean it never helps. So I’m glad that Sara Gilbert is joining The Big Bang Theory as a regular, because her guest appearances last season clearly showed that she fit in perfectly with the main cast, and that she was much funnier than the female lead, Kaley Cuoco. Also, a show whose regular cast consists of four men and one woman is a little imbalanced. Even Two and a Half Men has more women in the cast. The Big Bang Theory is already a more appealing comedy than Chuck Lorre’s other show, Two and a Half Men, much less nasty, and performers like Jim Parsons and that guy from Dr. Horrible have really established themselves as first-class comedy characters. (Ironically, the two most “established” performers in the cast, Johnny Galecki and Cuoco, have been the ones who have made less of an impression; Galecki will be helped by having his old Roseanne chum Gilbert around full-time.) So while the hint of desperation is clear — TBBT has done well, but failed to build much on its strong start, and the producers are obviously hoping that Gilbert can give it the boost it needs — it may be “good desperation.”