Only acceptable it the movie is made into a trilogy or something. I really hope the Part 1/Part 2 thing doesnt catch on. Its just a ploy to make money from a limited amount of source material and stretch it out over 2 payments of 8 or 9 dollars.
After seeing each heroes individual movies, I want to see how the producer will make them interact with each other. Although it's called the Avengers, I think it would be a nice little tidbit is they showed some of the sub-characters from the other movies like Loki or Warmachine.