Re: Should the archenemy be first?
It depends entirely on the franchise and the nature of the conflict between the protagonist and his arch.
Like, take Green Lantern for example. Not the actual movie, because I didn't see it. But if I was doing a GL flick, I'd start with Sinestro as the villain, with the first movie having him be Hal's partner only to betray the Corps and turn dark side by the film's end, and have him remain the main villain throughout the movie franchise.
But Nolan was right to save The Joker for the second film.
It really depends on the franchise.