The science (by the way) doesn't bear thinking about. His internal organs are shut down, his blood doesn't circulate, but his brains and muscles work and he can speak (though he can't breathe) and he's not decaying. So how does that work exactly?
Dr Who has its duff episodes too- any long running show is bound to- but it's alive and in good health and there were at least three episodes in the last season that were as good as it gets.
So what's wrong exactly? I reckon it's the chemistry. Buffy- which is pretty much the model for Torchwood- could be stupid and tiresome and underachieving too- but it was held together by a wonderful team of actors- with "team" being the operative word. That show isn't so much about vampires and saving the world; it's about friendship. And that's why we love it- because we all wish we had a circle of friends as attractive, entertaining and as staunchly loyal as the Scoobies are.
There have been attempts to make the Torchwood gang more interesting. Captain Jack has regained some of the cheekiness that made him attractive when he was the Doctor's sidekick, Ianto has been gifted with a dry wit, Tosh has been given emotions- but they still don't really gell. To be brutal, I don't think these actors are good enough. They don't have the whatever-it-is that would make us care about them- or inspire the writers to deliver out-of-the-ordinary scripts. The exception- Burn Gorman- who is stange and freakish and unique (he was wonderful as Guppy in Bleak House)- is now saddled with the restricting role of dead man walking.
If I were Russell T (or God or whoever) I'd have the whole team bar one wiped out by the explosion of an alien artefact and rebuild the series round Gorman- but Russell loves his actors and would never be that ruthless, so it's not going to happen, is it?
Don't get me wrong. Torchwood is well made, it's good fun, it's often quite exciting- but does anyone love it the way some of us love Dr Who or Buffy or the X Files or even Blake's 7. I doubt it.