Normally, I dislike the idea of revivals of shows. Typically speaking, if they're remakes, they all too often miss the chemistry of what made the original shows great (listening to Lisa Loring recently on the Monster Party podcast, and as she pointed out, every remake they've done of The Addams Family has lacked what made the original show a classic, even though I love the 91 movie). And if it's an actual revival like the ones you mentioned, they sometimes feel like nothing more than nostalgia grabs (although, I like what I have seen of the new Murphy Brown, and while I passed on Roseanne, I like The Connors). And, let's face it, the Star Trek movies were nothing if not bigger budgeted revivals, and four out of the six are quite good.
However, having said all that, there are a few shows I wouldn't mind seeing brought back, if for nothing more than a six or eight episode mini-series, just to see what happened after we left them. But again, I feel like all it would be is a hollow pantomime of what the original product was, and would just be disappointing. I say we start looking for new stories to tell from new writers. Say, an unknown from the American midwest who has some very interesting ideas. All one would have to do is call, I don't even have an agent to go through.
I just think that any and all revivals get messed up - except when they do a new riff on an old theme. I am thinking of WESTWORLD here, although even that topples over into being excessively violent a lot of the time.