Fans are already aware of one major change for Ultron in The Avengers 2 with no Hank Pym as part of the origin.
Now Joss Whedon hints at more changes for Ultron in The Avengers 2 as well with the taking away of some of its powers for a more grounded approach.
Speaking with EW, Whedon offers the following:
“I knew right away what I wanted to do with him,” Whedon says. “He’s always trying to destroy the Avengers, goddamn it, he’s got a bee in his bonnet. He’s not a happy guy, which means he’s an interesting guy. He’s got pain. And the way that manifests is not going to be standard robot stuff. So we’ll take away some of those powers because at some point everybody becomes magic, and I already have someone [a new character, Scarlet Witch] who’s a witch.”
Whedon adds that he has to be careful “to ground [the character] while still evoking that guy.” And like a certain giant green Avenger hero, it sounds like large doses of rage will be key to his personality. “As a character I love [Ultron],” Whedon says, “because he’s so pissed off.”
Depending on the version, Ultron's powers in the comics include: flight, energy blasts, invulnerability (armor made from adamantium), self-repair, genius intellect, use of electomagnetic radiation for energy source, an "encephalo-ray" which can enduce coma and mind control, ability to maniuplate computers, consciousness becoming radio waves and more.
Regarding Ultron's origin in The Avengers 2, it's speculated that Tony Stark may be involved as in the Comic-Con teaser it showed Iron Man's mask transforming into Ultron. Marvel Studios also likes to borrow heavily from the Ultimates, where Scarlet Witch played a role in Ultron becoming sentient.
The Avengers 2 hits May 1, 2015. Head on over to the Cosmic Book News Avengers movie hub for more.