I was thinking yesterday that voyager would have been a lot better if they had killed some of the main cast off every now and then.
I think it could have added more suspense as you would never have known what would happen each episode rather than know that the main cast would always pull through ok.
The problem is people get attached to characters with a show and you kill enough off, the audience will face attrition and the show becomes a sort of anthology with continuity. There's the issue of emotional commitment to a show. And also such a tactic leads to death for deaths sake (as was cited with Stargate Atlantis. That was the case with Beckett and that did NOT go over well. Same could be said for Trip's gratuitous death in the Enterprise 'finale' and Joe Carey being offed and Admiral Janeway not giving a damn to go back 1 month earlier so his children could have their father back when they return home in 1 months time). The concept leads to some ghoulishness and sadism on the part of some writers.
The idea of a cast where no one is safe is one many get enamored with, but in practice it becomes problematic. Would be funny to apply it to a family sitcom though, especially if they start with a Brady Bunch-sized cast.