I'm only one episode into Miracle Day, so perhaps it's too early to judge. But with ten episodes in total, it had better improve or I'll be unwilling to invest more time in it.
Notwithstanding my initial reservations, the theme of the story made me think again about miracles. As I see it there are several ways to define a miracle, two of which are:
1. A miracle is something that can't happen.
2. A miracle is a happening that proves the existence of God.
So if religious apologists insist that a miracle might be an extraordinary event that appears to contradict natural law, they can't use it as proof of God's existence if the event is unlikely but not impossible. God's existence could only be proved by the occurrence of an impossible event. But then you have the problem of defining what's possible and what's not. Taking the Torchwood — Miracle Day example, the miracles are described as such, but there are plenty of people in the story who are looking for some kind of natural explanation, and surprisingly few who take them as examples of God's inscrutable ineffableness. Writer Russell T. Davies is an atheist, but he's not above grappling with religious issues, as he did with The Second Coming.
Personally, I go with the first definition of miracles. Which leaves the second definition high and dry.