People love the What if scenario For comic books, for sports, for TV shows, and obviously for movies, especially when it comes to endings. Thinking and debating alternate endings can lead to fruitful discussions, rabid arguments and as you can see, some pretty awesome artwork.
While the first one, from a personal favorite of mine, Se7en (or Seven sins in some countries), seems highly unlikely to be actually an option going through the minds of the people who made the film, the others are kind of easy to imagine. The Plant of the Apes with a romantic resolution, Blade Runner having yet another ending or Batman actually losing at the end of one of the movies.
Too bad… a lot of people were happy to see Gwenyth Paltrow not making it all the way through the movie.