It has been done before and I'm in favour of it if it's done with the full knowledge and consent of everyone - the person dying, obviously, and their immediate family and close people. Death is part of life and although we see representations of it all the time on the screen, we so rarely see real death.
Taboos should be challenged, and, done properly, this is something television can and should do well.
My reservations would come if people's deaths were degraded by being on television, as in, for example, the televising of an execution. I didn't watch any of the footage of Saddam's death, nor have I watched any footage of any other killing of another person. It's degrading in the extreme.