No idea why this came to mind, but in the movie Forbidden Planet, the monster turns out to be Dr. Morbius' id, unleashed because he increased his brainpower with alien technology.
Theory: Mark Millar is Garth Ennis' id monster. It's all of the profanity, violence, sexual content, without any of the emotional content or themes that Ennis has in his better work. So it comes off as half-thought out ideas designed to look "cool" or "adult", but are really more juvenile. Not that Ennis doesn't himself produce that kind of crap, but Dr. Morbius didn't keep all his anger and resentment completely under wraps either.
I know what you're saying, Mark Millar has written good stuff, too. I'm just letting my negative feelings about Civil War bias my perspective. And maybe you're right. But first off, I'm not convinced Mark Millar actually exists. I've never met him. He could be a bunch of squirrels in a track suit for all I know. Second, there's nothing wrong with being the monster, necessarily. It gives everyone else something to struggle against, so without it, there wouldn't be a show. How many fewer posts would this blog have if Mark Millar hadn't written a really bad mini-series called Civil War? A lot less? He carried that burden when no one else could, when I was only weary of Bendis, and long before Jonathan Hickman had gifted me with the chance to make snide remarks about Reed Richards being bad at building a universe.
So it's not all bad, being the id monster.