Watchmen Director's Cut is worse than the theatrical cut. It adds nothing new of importance, and only serves to make the movie longer. I can't even begin to imagine why some things were added to the directors cut. Oh here's a new dumb scene of Rorschach looking at a cop so hard that he misses all his shots, guess it was added because other than the sex scene the theatrical cut is so light on comedy. The only big thing that seems to added anything is the Hollis Mason scenes. The only thing is they don't added anything, because Hollis Mason's death was folded into Rorschach's death in the movie...which means in the directors cut you have the same thing happen two times in a row. Mason's death also only further illustrates how much Zack Snyder does not get the material he's adapting. He took a scene of an old man being beaten by random punks that was juxtapositioned against his glory days of beating masked villains, and turned it into a scene of old man Manson kicking ass with every hit flashing back to him kicking ass.
Watchmen is a pretty awful movie, with the only good thing in the whole thing being the Doctor Manhattan sequence with the Koyaanisqatsi music. It's weird how focused Snyder is on the mystery aspect of the Watchmen comic, (which is the least interesting part of it) but then precedes to remove parts of the comic that would make that stronger. It's also weird how completely humorless the movie is, the comic isn't without humor, but besides some unintentionally funny scenes (like the sex scene) Watchmen might be one of the morosest movies ever made.