Why Ultron is in ‘Avengers 2′ Instead of the ‘Ant-Man’ Movie
This is, as stated, a bold deviation from Marvel canon – one that will inevitably leave some fans upset – which is why Ant-Man writer/director Edgar Wright discussed the reasoning for keeping Ultron’s origin out of Hank Pym’s movie, while speaking with Huffpo:
[Ultron] was never in my script. Because even just to sort of set up what Ant-Man does is enough for one movie. It’s why I think “Iron Man” is extremely successful because it keeps it really simple. You have one sort of — the villain comes from the hero’s technology. It’s simple. So I think why that film really works and why, sometimes, superhero films fail — or they have mixed results — because they have to set up a hero and a villain at the same time. And that’s really tough. And sometimes it’s unbalanced.
You know, when I was younger I used to love Tim Burton’s “Batman.” I was like 15 and even then I was aware, “This is really the Joker’s film.” It’s like, the Joker just takes over and Batman, you really don’t learn too much about him. Comics haveyears to explain this stuff and in a movie you have to focus on one thing. So it’s about kind of streamlining, I think. Some of the most successful origin films actually have a narrower focus. You cannot put 50 years of the Marvel universe into a movie. It’s impossible.
With that mind-state, Wright seems to feel extra fortunate that his subject is Ant-Man, a superhero that is far from mainstream in the minds of casual moviegoers:
I think there’s something in that it’s a lesser known character, there’s hopefully more license. For the one percent of people who are like, “Wait, Hank Pym would never do that!” there’s 99 percent going, “Who’s Hank Pym?” So, to me, the source material is great but it also frees you up to be like: I’m going to make a movie. The movie is not going to represent 50 years of Marvel comics because that’s impossible. But I’m going to make a 100 minute movie — or 110 minutes [laughs].
http://screenrant.com/avengers-2-age-ultron-ant-man-movie-origin-discussion/