As I understand it the original concept for what became Watchmen actually used the DC characters. That idea was vetoed and then later we got the Watchmen we're all familiar with.
Actually it used the Charlton Comics characters that DC had recently acquired, including Blue Beetle, the Question, Captain Atom, and others. The plan was to do a big event to commemorate their addition to the DC Universe. But Moore's ideas left most of them pretty much unusable afterward, so they were replaced with pastiche characters -- Nite Owl for Blue Beetle, Rorschach for the Question, Dr. Manhattan for Captain Atom, etc. And DC went on to incorporate the Charlton heroes into the mainstream DC Universe by other means.
Some of the reviews I've read allude to The Flashpoint Paradox as being rather like Watchmen but going back and using the DC characters. And being an an alternate timeline they can get away with that idea. I admit that's part of what intrigues me about this feature.
I'm not sure I'd say that. Okay, sure, it does the same thing comics have been doing for decades now, imitating
Watchmen on a superficial level by being all dark and dystopian, but it certainly doesn't have the same kind of philosophical depth or originality. It's really just another example of a trope that we've seen many times before, the alternate-timeline story where the writers can make everything as horrible as possible and have everybody die because it's all going to be undone at the end anyway. I found the movie rather gratuitously dark and violent, and it didn't do much for me, as I recall.
Flashpoint was absolutely not about doing a story on the level of
Watchmen. It was just an excuse to reboot the continuity and launch "the New 52," although there was no clear justification for why the events that altered and then semi-restored the timeline would bring about the particular changes they made to the universe.
