Are villains better when we can see their perspective? Is it more believable to know that the villain is angry because he's lonely, or because he was abused? Or are purely evil villains just as compelling if they're written correctly?
The villain in First Light was rather flat. We never got her side of the story, and she was consistently mean without explanation. She seemed to believe she was doing right for her community, and an argument could be made that she had their best interests at heart. But it wasn't.
The story wasn't about the villain, though. It's about Thea, the end of a long line of women who escaped persecution by settling inside a glacier in Greenland 200 years ago. They're able to live down there because they are (in some ways) more technologically advanced than the wider world. (These are the sci-fi/fantasy hurdles.) It is also the story of Peter, the kid who finds them.
It's an interesting enough story that I read it pretty quickly, but I wouldn't say it's quality reading. There are lots of loose ends and things that never get explained, so that's dissatisfying. Like, they live inside a glacier, but it's not terribly cold, but the major travel routes are icy, and they use skates with blades that flip up and down. This is the technology advance. Also, the first time through the tunnel, there's water pouring in from somewhere (never really explained) and the rest of the time it seems dry (also never explained).
The attempt was there to discuss global warming, glaciers melting, even mitochondrial DNA, but none were addressed explicitly enough to have a real impact on the reader.