Re: Avengers Sequel ideas?
I think Ultron would be an awesome Avengers movie villain, but I feel he should be used at least one movie after Pym is introduced. If Pym comes in and all of a sudden is behind the main threat it would seem pretty bad on Hank, but once he's been established as part of the team, then he can accidentally create an evil robot and audiences will accept it more. Of course they can introduce him much earlier as a harmless robot but he should go evil until later.
Having Stark help create Ultron like in AEMH is a great idea and I can see them going the same route if they ever use him. One of the problems that they might face though is how cliche a storyline of an evil AI has become in cinema and they might need to take some liberties in order to keep it fresh. Despite the problems he has, Ultron is a huge part of the Avengers History and should totally be used at some point.