Totally agree with your statement, and you have some cool choices in there. Love Watchmen, everyone I know hates it.
In regards to people saying the older X-men is crap, I think that has a lot to do with time passing. With Avengers bundling them up and Marvel dishing out movies at record pace the licenses remain fresh, so it is a lot cooler to like those (= mainstream, don't try to deny it).
Same with Spiderman, after Amazing the previous trilogy is supposed to be crap? Did you think it was crap when they released?
After Dark Knight premiered Nolan Bats was considered #1, after that IM, then Avengers. And nowadays a superhero flick needs borderline ridiculous action to be classified as one. When those effects are surpassed in the future, the movie has to have something else to remain enjoyable.