One of the running themes with Doctor Manhattan is that since he perceives time and history as progressive event, and experiences events from his past and future as being preordained, he is resigned to fate. Or what he perceives as fate. It never occurs to him that he actually has power over events, that he can make a choice and be proactive, that he can involve himself in a beneficial way. Another irony that feeds into the way his view on the world is shaped is the fact that even his name, Dr Manhattan, is something that shapes him. A name he never cared for it was thrust on him by others. And the way those others, the destructive paranoia of the military, shaped the worlds view on him became a part of the way in which the likes of Ozymandias saw him - as an asset and weapon, and something to be exploited as such...
These are the forces that helped shape Manhattan's worldview and actions.
I don't care for Doomsday Clock and its commercial bankruptcy, but in a sense I do appreciate the themes Geoff Johns tries to tackle here, he doesn't do it to my satisfaction but I do still appreciate the aims he was trying for.
The story of the aloof and emotionally disconnected god who was once John Osterman meeting a very special person, much like Silk Spectre, who shows him the flaw in his worldview and forces a profound self-realisation within him, is one worth telling. It is a story about choice, the choice everyone has to choose life, to do the moral thing and do what is right. I don't quite agree with Johns' choice in using The Watchmen as a lever to explore and instill this lesson as that completely misses the point of what that world was (and is) all about. But as I say I do appreciate the honourable intentions that Geoff Johns had with this project.
The entire point to me of the storyline was that Superman is the ideal, is the moral center of the DCU, and that Manhatten finally learned from him that with great power comes even greater responsibility!