James at 2010-04-25 15:15:05:
I think this question is two fold.
Yes, it is a problem if your antagonist isn't "bad" enough. He needs to oppose the protagonist at every turn.
That doesn't necessarily mean he needs to be evil.
The easiest way to create conflict is by having two characters who want the same thing.
Two guys want the same girl. They could even be friends. One is a likable underdog. We'll decide he's our protagonist. We get to see things from his POV and like the guy.
The antagonist is suave and sophisticated, maybe well off. Everything the protagonist wants to be, this guy already is -- and more. He one ups the protagonist at every shot. And maybe he doesn't even know it.
You don't have to have bad intentions to be an antagonist. Just be a huge obstacle.
The problem is -- to not make the antagonist too likable. Otherwise, he may compete with the viewers for who they think should actually get the girl.
I felt the NOTEBOOK had this problem. James Marsden's character was noble. To the point, he actually stepped aside. It made me think Ryan Gosling was a whiny broody turd. Things became muddy.
TITANIC on the other hand was criticized for the villain being too Disney -- a cartoon. He was evil to the point of contrivance. Like instead of getting on a boat to save his own neck (which was well within his character) he went out of his way to make sure Jack was killed aboard the boat. Hello? It's sinking and there's not enough boats. I think you're covered.
I think it's quite possible to be somewhere between these two. I think finding that balance is the craft of screenwriting.