In a way it is a Biblical literalist's dream. Check this dialogue from the transcript on my website:
"(Julia) Then... why did you come here? You have powers at your command, why don't you bring Eve to life?"
"(Nicholas) If that were the case, I could have used them to avoid the first two experiments. Why didn't I do that?"
"(Julia) You tell me."
"(Nicholas) Because it was imperative that Eve be created artificially, the same as Adam was."
"(Julia) Why?"
"(Nicholas) For the answer to that, I refer you to the book of Genesis. The original Adam and Eve were tempted by the Master."
"(Julia) By... Satan."
"(Nicholas) I know him... by another name. At any rate, the first man and woman yielded to temptation, sinned against their maker. For this they were punished. But they remained his children nevertheless. Now... now after thousands of years, there is a new Adam, a new Eve! Different from every living human being and yet... human, just the same. And they, and all who they breed shall be the children of my master!"
"(Julia) It's... monstrous!"
"(Nicholas) Yes. It is intended to be."
Side Note: This makes the whole Diabolos business even more convoluted than it was. The original idea was that having the Devil on TV was a bit too much, so they filed the serial numbers off and made him "Diabolos", a Prince of Darkness, but not any particular one, mind you. Of course they never called him that onscreen, so you had to read the credits to even notice it. But now Nicholas comes flat out and says that Diabolos is Satan, making you wonder what the point of the name change was in the first place. That's why my page has that one caption that always cracks me up no matter how many times I read it:
"(Nicholas) Genesis, Chapter 3, okay? Adam and Eve were tempted by the Master."
"(Julia) By Satan!!"
"(Nicholas) I know him by another name. A super secret name. A name that no mortal has ever heard and lived to tell the tale!"
"(Julia) Oh, you mean Diabolos."
"(Nicholas) D'oh!"
Anyway, it's true that Nick and Ang are the bad guys, but I can buy the idea that some might not think it a great show for kids. Like Peyton Place, there really are no Good Guys, or very few at least. On DS it's usually less Bad Guys vs. Good Guys than it is Bad Guys vs. Not-Quite-So-Bad Guys. From seeing it as a kid, I remembered Barnabas as being a good guy, but when seeing it years later, was surprised how seldom he was. Well, Julia was a good guy, at least. No, not really her either. Seeing it again years later, I was surprised how quick she was to abuse the doctor/patient relationship with Maggie, and cut corners whenever necessary to get what she wanted. At first she seemed to have some idea of winning the Nobel Prize for her anti-vampire elixir or something, and after that, she was Barnabas' enabler.
It's a good show, but not a great show for kids, as there are no real role models. Everyone is either deeply flawed, or perennially out of the loop. Some struggle against their flaws harder than others, but there's really nobody you'd want to emulate, at least not consistently. People have little flashes here and there. It really is like a supernatural Peyton Place, which wasn't a show for kids either.