Regarding Watchmen...I thought it was a pretty good adaptation, all things considered. And I always felt like it didn't do as well because people were expecting a super hero closer to the expected norm of super hero movies. In short, they didn't expect it to be a murder mystery also dealing with the "what if" like conceit of "what kind of impact would these people realistically have", etc. Or the complex notion of the "bad guy" doing what he's doing for a greater good.
The needs of the many outweigh the needs of the few, etc.
They'd had enough super hero movies at that point, and ones that followed a fairly basic pattern, to have formed a certain kind of expectation of what a super hero movie *is*.....and they got something else.
I could be wrong though.
Regarding the release of X-Men:FC in Sept..... IIRC, one of the fastest movies to come out on video was Tim Burton's Batman. In those days, the good movies took forever to go on sale to the public....and at first, they'd be expensive...then they'd drop to about 20.00 bucks or so. But Batman came out on video tape, quickly and cheaply. I recall at the time being amazed at the speed and also thinking that this is how it should be done...strike while the iron is hot.
And they did. It was also the first time I recall video tapes of movies being sold in places like Walgreens, Krogers, etc. For YEARS you could pretty much bet that anyone who bought video's had a copy of Batman in their collection. It was the one movie that everyone I knew, comic fan or otherwise, had in their collection.
They never let the audience get hungry for Batman and they reaped the rewards for it.