Re: Avengers Sequel ideas?
The issue is that Ultron has a crazy emotional connection to Pym, and none at all to the other characters, thus, he doesn't serve as well as a team villain without predominate focus being put on Hank Pym, as it has in past Ultron storylines.
They can do this with Loki because not only can Loki make emotional relationships with the rest of the Avengers very quickly and relatively easily, being an emotional being, but he can leave his origin behind basically, and Thor being his brother becomes incidental. In Ultron's case, his Oedipus complex is pretty much the central tenet of his character, and because of that, the most satisfying endings involve Pym confronting him on that level. In Avengers, Thor and Loki was out of the way pretty early. Stark was the one who was figuring out Loki's plot, and Hulk is the one who ultimately physically defeated him. I don't think that would pay off the same if Loki's entire motivation for all his actions was his relationship with Thor.