The question of which characters were more or less right or wrong in Watchmen is left up to the reader to ponder. Heck, the whole thing with the Comedian and Sally and Laurie is the same way. The Comedian does some absolutely horrible, evil things, yet there's still a humanity there which really comes out later on when you put the puzzle pieces together. I think in this period, basically the 1980s, Moore explores a lot of "what does one do with superhuman power?" concepts in his stories. For those who haven't read all of these, SPOILERS FOLLOW.
In Swamp Thing, we see Alec decide that if he fixed all the world's ills, mankind would never learn to take care of itself, so he decides to retire with Abby to his own little part of the swamp and take care of the local people there (giving them great harvests, etc.), but leaving the rest of the world on its own.
In Marvelman/Miracleman, he decides to take over as a benevolent dictator, which makes things better in many ways but still leaves the sense that this is not perfect either; we even see a character feel sorry for Margaret Thatcher when, defeated, she realizes that the world order she's been a part of is basically no more.
In Whatever Happened To The Man Of Tomorrow, Superman gives up his powers and fakes his own death to retire with Lois, embracing ordinary humanity and letting the world take care of itself, suggesting that his sense that he had to keep acting as a super-hero was really a kind of arrogance. Still, things are not going to stay that way forever -- his baby has inherited his powers as we see with him crushing a lump of coal into a diamond.
In Watchmen, Veidt "saves" the world by secret manipulation, but at great moral cost, and possibly all will be undone by the finding of the journal. Meanwhile, Dr. Manhattan just leaves humanity on its own and may be off creating his own world elsewhere.
In V for Vendetta, V destroys the system but does not put a new one in its place, and becomes a symbol in the end rather than going on to build a new order.
So I think in each one of these storylines, Alan is exploring the nature of power, how it affects "the system," different answers to "what does one do with power," and so on, and none of it really has a definitive, absolute answer. The closest things to happy endings we see with characters who have power seem to be Swamp Thing and Superman, and in both cases they are pretty much stepping away from trying to "fix the world" and just, in a sense, embracing their basic humanity (living quietly with loved ones). As well, the characters in Watchmen who seem most fulfilled at the end are, despite all the issues they may still have, the most ordinary human ones: Sally and Laurie and Dan, going about their lives. Basic human affection, romantic and familial, seems to be the common thread for the characters who have definitively happy endings in these stories.
I would even slip The Killing Joke in here, in fact, though it's more subtle than these others -- despite the Joker's horrible crimes, personally committed against Gordon and his daughter, when Batman goes after him, Gordon still insists that Batman does it "by the book." The Joker has put himself outside the system, and Gordon wants Batman to stay inside that system even though it would be easier to step outside it to stop him. In a lot of ways the story is about Batman's rejection of any temptation to put himself truly outside the system of regular, human, societal laws and ethics, even for the perceived greater good -- and in the end, as the police arrive, he is even able to make contact, however brief, with the spark of humanity still in the Joker.
So in all of these cases I'd say that if there is a consistent message in Moore's 1980s super-hero work, it's that one's basic humanity, with all its flaws, is to be embraced, and that those who put themselves truly outside the system -- even for the potential good that could arrive from doing that -- are still missing something vital.
