I haven't seen the movie yet, but people bitching about realism and historical accuracy obviously haven't read the comics--or they missed the point.
Yeah, the comics aren't historically accurate. They're -mythic-. It's meant to perpetuate the legendary elements of the story, rather than reducing it to a cold documentary. There's a very long tradition--including the ancient Greeks, up to the romantic Classicists--of portraying heroic figures nude or semi-nude, as a way of highlighting the aesthetics of their bodies, and the 'purity' of their acts as symbols.
And while Miller might not have been explicitly imitating classical Greek art forms, he's definitely more interested in choosing his artistic style for visual impact rather than as a way of literally representing historical accuracy. The book is fucking full of panoramic shots of perfectly aligned, symmetrical shield-walls, Spartans uniformly [un]equipped with cloak, helmet, shield and spear, and so on. The implied comparison of Leonidas, naked and toting a spear, with Xerxes, pimped out with enough piercings and chains to sink a boat, is about as subtle as a kick in the crotch.
And yeah, the story has jack shit to do with 'freedom' in the modern since--it never has, and doesn't in Miller's retelling. It's oldschool, macho, military self-sacrifice. Hell, it's the myth of military self-sacrifice, as far as the modern world is concerned. The closest thing to 'freedom' is the idea of fighting for one's homeland against foreign invaders, which has been inspiration for all sorts of unfree armies throughout the ages, including Stalin's Red Army and Hitler's Wehrmacht. Frankly, I'm not even sure what makes people think the movie is about 'freedom' to begin with.
One of my favorite bits from the comic, which isn't in the trailer and may or may not be in the movie... when the Spartans arrive at the mustering point for the Greek armies, one of the other city-states' soldiers says, "I thought the Spartans would have sent more soldiers." Leonidas (or Dienikes, I forget) asks them what their professions are, and they respond farmer, potter, merchant, etc. Then he asks his own Spartans what their profession is, and when they all lift their spears in the air, he says, "See? We still brought more soldiers than you." That's pretty much what the movie is about: rah-rah militarism, of the oldest sort, essentially much unencumbered by any moral subtlety or political nuance.
So, yeah, I'm looking forward to it.