Well on the heroes point - You can pretty much swap the DNA for Magic and vice versa. It's just a really old story telling trick dressed up in science.

I like Merlin, it had a few duff moments. The Dragon was a bit naff.
Though it's a lot better than Robin Hood, mainly because Merlin is likeable where as Robin is a bit of a twit really.

Oh and even better news - Michelle Ryan is in episode 3 as the evil sorcess (sp?) Nimueh. She's apparently the big bad of the series. And nice to look at *whistles*