I've come across so much deconstruction regarding the book going in that the plot wasn't a surprise (though the meticulous detail in the panels was admirable). What preoccupied my mind instead, then, in a missing-the-point way, was how little I enjoyed the company of the comic's world and characters - how I felt like I needed to wash afterward. And, yes, of course this unpleasantness (to understate prissily) is integral to the book's message. I find it unfortunate, though, that the grimdark aesthetic was what the U.S. comic book industry apparently took from Watchmen, instead of following in its literary ambitions, its crafting of characters and moral dilemmas that hold up to extended analysis and scrutiny. (That said, its message is quite self-reflective - a treatise on why the concept of superheroes doesn't work - and while the argument is well-considered, it still seems a...lesser undertaking than "typical" novel considerations of the human condition and other larger issues. I'm not claiming Watchmen's message was unworthy, but I wish the Greatest Comic was something a bit less navel-gaving, is what I'm saying.)
A purposefully vague thought concerning the last "I leave it entirely in your hands" bit; does not the claimed context of the closing "Quis custodiet ipsos custodes?" quote indeed imply that, well, something was done?
P. S. That site I linked's piece on the Trayvon Martin case, "that's just the way it is.", is the best I've read on the issue and well worth reading.