The DAWN OF THE DEAD remake wasn't a good film. It was a passable horror installment at best, and definitely not the caliber of film that says, "Hey, I'm the perfect choice for WATCHMEN!" In fact, it indicates the exact opposite.
Now, I haven't seen 300, but I know the comic pretty well. And there's no way that comic as it's being adapted will truly be an utter masterpiece from which I would say, "This guy should do WATCHMEN." It's probably going to be a blast to sit through with some great visuals, but WATCHMEN is so much more than that - it's a character drama with heavy thematic material and it requires an incredible amount of skill to transfer that from the page to the screen.
WATCHMEN is the holy grail of comic books, and if the crew behind it aren't some of the finest filmmakers around, it shouldn't be made. Zackri Snyder has yet to prove himself as an master filmmaker, and thus, I don't think he should be given this project.
Well that settles that, then.