Re: Should the archenemy be first?
Yes, it should. Most of the time, the only reason an archenemy debuts in a sequel is usually because its a rebooted version of a character (Ex: Nolan's Batman, Webb's Spider-Man, and now Snyder's Superman).
If you're doing a character for the first time, it should be understood that sequels aren't guaranteed, so the first film should represent the best of the character as much as possible. That's why most of these superhero big screen debuts have their archenemy upfront, and thats how it should be. "Green Lantern" was foolish not to have Sinestro as a villain from the start.
"There is a difference between you and me. We both looked into the abyss, but when it looked back at us... you blinked."