I liked the Hulk a lot and Ang Lee could well have done the metaphysical side of Watchmen very well. Not so sure about the action, though.

I wasn't concerned with the liberties taken with the Hulk's saga, either. Had there been a long-running series of Watchmen adventures, then I reckon we would be more relaxed about how closely the film will adhere to the book. Take the novel "Frankenstein — a modern prometheus". Most of the films of note have diverted greatly from the novel itself. The first two Karloff films are true classics in the genre while the fairly recent Branagh version which followed the novel more closely is more of a failed footnote.
What I am getting at is that most of the audience of Watchmen will have not read the graphic story — some would have never heard there was one. It will be a movie and will work or not on those grounds.
Snyder's visual flair (as seen in 300) will work nicely if he stays with the program. The way the "deeper", "acting" parts of 300 were filmed lead me to think that he had better pull his socks up, though. There is some tricky dialogue that will have to be played very cleverly to not appear camp or unintentionally funny. That
isn't just up to the actors. (Take SW I, II and III as examples! — fine actors pontificating in front of a director unable to get it right)
But as I am more interested in eye-candy, then I reckon it will have to do. 300 worked fine on that level.

As for my dream-directors that could handle this...
I'd like the guy that did 12 monkeys, but not the guy that did The Adventures of Baron Munchausen.
I'd like the guy that did Psycho, but not the guy that did The Birds.
I'd like the guy that did Schindler's list but not the guy that did Hook.
I'd like the guy that did The Killing but not the guy that did Eyes wide shut.
I'd like the guy that did Spiderman, but not the guy that did Spiderman III.

The french chap — Jean-Pierre Jeunet — that did "Le Fabuleux destin d'Amélie Poulain" and "Un long dimanche de fiançailles" is clever with visuals, and can get people to act. (Audrey Tautou as silk spectre?).
The guy that did Pan's Labyrinth, Guillermo del Toro, did a fantastic job. He got some great acting out of his team for that one.