My 2 cents on the prequels is that I'm siding with Alan Moore on this one. Not from any highfalutin' creator-rights perspective, but the fact is since Watchman was simply a riff on existing superheroes (the fact he planned to use the Charlton characters, etc) then if they do prequels, all they're just going to do are rehashes of stories and characters of years gone by. And while from a purely prurient perspective the idea of seeing more of Silk Spectre I and II is appealing (especially if the former is drawn to resemble Carla Gugino from the movie; Silk Spectre II I thought was hotter in the comics; no offense meant to Malin A.) I just fail to see the point. That said, DC has been threatening to do a sequel or prequel for Watchmen since Watchmen came out, so no one, including Moore, should be surprised they finally decided to do it.
I expect to see DC announcing Dark Knight Returns Again, Kingdom Come: The Revenge and Another Killing Joke in the near future.
Alex