I can't even work up Kevin Drum's conspicuous lack of enthusiasm. The film's biggest problem: the characters open their mouths and, gulp, speak. Now, this might not be so bad were the characters speaking something akin to Homer's poetry. Instead, we get dialogue so wooden that it's petrified (and actors clearly petrified by the thought of speaking the dialogue). Of all the performers, only Peter O'Toole as Priam seems believable as a truly legendary figure, and that's partly because everyone else around is so blah. Brad Pitt's Achilles has muscles but no charisma, Brian Cox's Agamemnon chews many holes in the surrounding scenery (and, much to the surprise of anyone with a background in classical drama, winds up with an extra hole himself), and Diane Kruger's Helen has a face that might have launched five ships but not a thousand. We really don't need Passionate Romance between Achilles and Briseis; meanwhile, what's the deal with Patroclus becoming Achilles' cousin?
At times, the film tries to have Ideas. The very domestic Hector is a true, selfless patriot, whereas Achilles (first glimpsed recovering from a night of group sex!) is a Rugged Individualist with no interest in Greece qua Greece. Indeed, the script argues that Greece is a jury-rigged nation with no inner cohesion, cobbled together out of Agamemnon's lust for power instead of organically united by bonds of patriotic love. By contrast, Troy commands love because Troy is a singular and literally self-enclosed city. To a certain degree, then, Achilles has an excuse for pouting; as far as nations go, there's no there there.
UPDATE: Hmm. David Edelstein wants to grant Helen a few more ships.