I enjoyed Dark Knight Returns, even while seeing Miller's politics. He overmilitarizes and desperately dehumanizes Batman. I saw the story, a bit, about what could go wrong with the Batman as a self-indulgent moralist. His more recent works on the character have been fairly divisive among the fans--for exactly the reasons you outline.
Years later I found his sequel to DKR in a bargain bin at Half Price Books. It was an extended "fuck you" to the fan base that made his career possible. It's clear throughout the comic that he resents making this book and intentionally made it as bad as possible and threw in as many crappy mock mischaracterizations of beloved second string characters in the DC pantheon specifically to tell the fans how lame they themselves were.
Miller's a libertarian, not a conservative. He hates religion too--a frequent theme in his works is mocking anybody's beliefs in anything other than some above-the-law vigilante having his way on the streets. Essentially he's a wank off artist. The prevalence of the May-December pairings of grizzled street vets with nubile, barely legal playmates in his works (his Batman works, his Sin City stories, etc) should tell you that. Another running theme involves the "real men" telling off the snivveling weaklings of society that hold the great ones back. It's like he was cloned from Ayn Rand's renal glands.
What Miller does well sometimes is convey the raw emotional truth behind that worldview. It's sick, but it has a certain atavistic register to male emotional drivers. The fear of getting old & impotant coupled with the impatience with a world that doesn't let me have my way. It's all ego-trip, of course, but an ego-trip that once upon a time he did well. Success is turning him into a self parody, as happens with so many artists.
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