I get that it's a zombie show... but there comes a point where you risk turning a lot of people off by killing a pivotal character.
If glenn is dead, they may have reached that point with me.
I think this show is something different, though. It's always been pretty clear that the only TRULY pivotal characters are Rick and Carl. People who know the comics already know that they're the only two completely safe characters.
The producers have never been shy about saying that they'd kill off anyone to move the story forward.
How many pivotal characters have come and gone already?
Shane
Lori (debatable on how pivotal she was, but I personally think she was)
Dale
Herschel
Lori
the Gov (although by the time he was killed he wasn't as pivotal)
Beth (she didn't start out as pivotal, but she became pivotal)
Tyrees
So far the one that's caused the most angst was Beth, I think in a lot of ways because she was a very sympathetic character who had a hidden depth and strength to her.
I think the two characters who might cause riots if they're killed off are Darryl and Carol.