The cast of every TV show has a weak link

Worst episode of The Walking Dead ever? Some (I among them) would say "Stabtown," last week's installment, earned that honor.

It wasn't the premise, which featured Christine Woods (Flash Forward) as an alterna-Rick, ruling over a bunkered hospital ward in Atlanta with selective admission policies.

No, the fault this time, dear Brutus, is the star. "Stabtown" reintroduced Beth (Emily Kinney), the wimpiest card in The Walking deck. I haven't missed her a bit since she vanished in last season's 13th episode, "Alone."

Kinney may be the most inexpressive prime-time actress since Mary Lynn Rajskub (Chloe O'Brian on 24). At least Rajskub had her signature scowl, patterned apparently on a 5-year-old who has just had her paste jewelry tiara swiped by a bigger girl.

All Kinney can summon is a subtle furrowing of her brow. That small crease is used to convey, well, everything: puzzlement, anger, attraction, disapproval, grief, joy. You're kind of dependent on the context to read her emotions.

The fact is almost every show has a weak link in the cast. But you try not to build an episode around them. It's enough that they suck the air out of every scene they're in.

Take Madam Secretary. After the pilot, I assumed it would be Tea Leoni's TV kids who would be the primary drag on the narrative. ("Tell Putin I'll call him back; I have to find Alison a date for the junior prom.")

But it's been Geoffrey Arend as the secretary's director of communications who is consistently deflating the show.

Aren't speechwriters supposed to provide eloquence? Arend's Matt Mahoney traffics exclusively in empty platitudes and gets flustered whenever he's called upon for a solution to some international crisis.

Adding agony to insult, we also have to sit through Arend's awkward and uninvolving love life as he painfully pursues fellow staffer Daisy (Patina Miller).

Really? Of all the characters at your disposal, this dullard is the one you put on the front burner?

Another sore thumb is Joe Mantegna on Criminal Minds. Not only is he completely unbelievable as a legendary behavorial profiler, but every time he opens his mouth, you'd swear he wandered onto the wrong sound stage, getting lost on his way to a Bowery Boys revival.

Sometimes you get an entire unit undermining a show's momentum, such as Kristin, Boyd, and Ryan (Amanda Fuller, Flynn Morrison, and Jordan Masterson), the drab family-within-a-family on Last Man Standing.

Or take the entire genius squad on Scorpion. You know you're in trouble when the most compelling actor on your show is an American Idol runner-up (Katherine McPhee) getting on-the-job training.

And do you remember when a segment with one of the correspondents on The Daily Show was a highlight rather than an instant imperative to thumb the remote?

The entire student body on How to Get Away with Murder is failing, but only Asher Millstone (Matt McGorry), the whiny, hypercompetitive scion of privilege, makes you want to transfer every time he's on the screen.

Kids are often a problem. Sally Draper (Kiernan Shipka) always had a curdling effect on Mad Men. We watched her grow up before our eyes - and it hasn't been pretty.

Modern Family has always been remarkable for its consistently funny multigenerational ensemble. But this season Luke (Nolan Gould) is starting to grate. The writers still give Luke great lines, but he's taking on a Screechian quality, straight out of Saved by the Bell.

Finally, Marry Me would be a great deal funnier without Gil (John Gemberling), a true party pooper. It seems every sitcom now has to have a pudgy, eccentric, borderline pervy best friend shoehorned in. Case in point, Andre (Zack Pearlman) on Mulaney.

I blame Tyler Labine, who did such magical things with this archetype on shows like Reaper and Mad Love that everyone wants their own slobby sidekick. They just haven't been able to decode how Labine is able to make these dudes so likable and funny.

But I digress. This column is really intended to be a suggestion to the producers of The Walking Dead. How about turning Beth into a zombie? It would make her character far more interesting.