Eh, between the two of them, they're just Batman, not sure of the huge draw. Rorschach is the violence, rage, and Detective side, and Nite Owl II is the rich guy with gadgets that dresses like a bird. And since they were partners, you've basically got Batman there.
One analysis of the film (and I'm thinking it was from Timothy Callahan, but I could be wrong) pointed out that, while he had read
Watchmen dozens of times, it hadn't occurred to him until he saw the film that the story is basically the ultimate Batman vs. Superman story, albeit one in which Batman is broken down into
three components.
Rohrschach is Batman-as-violence. Nite Owl II is Batman-as-tinkerer. Ozymandias is Batman-as-genius.
What impressed me about the movie is that, coming out of it, I
so wanted to see a solo Nite Owl film. Patrick Wilson kicked some serious ass as the character, and he invested Moore's loser with some emotional weight.
ETA: Damn, my memory's frightfully good, that I could remember one single five-month old blog post with that much specificity. Said
Callahan:
"Watchmen" is really a story about Batman vs. Superman. I never realized it before, because I was always reading it as a book about Charlton analogues, but the movie doesn't have that same context and so the movie becomes about the three aspects of Batman (the obsessed vigilante, Rorschach; the kind-hearted gadgeteer, Nite Owl; and the self-made fighting machine with a gazillion bucks, Ozymandias) in conflict with an ever-distant, alien Superman (Dr. Manhattan, obviously). As a Batman vs. Superman movie, "Watchmen" is pretty cool.
