Try this one: it's like making a story about Frankenstein's Monster without Dr. Frankenstein.
We've been over this many, many times. The only thing that separates Ultron's story from any other uberkiller robot is the psychodrama of Ultron's Oedipus complex with Hank and Janet. That's what's driven Ultron for five decades, even on up to the present-day Age of Ultron story arc (that doesn't have anything to do with the movie title).
So now....we get any other uberkiller robot.
Totally agree here. I don't want the Avengers to fight just another killer robot and taking Pym out of the equation really kinda boils Ultron down to just that. Now Joss may tack some sort of origin on to Stark as the creator but that seems totally out of place given what we know of Stark. Just pretty disappointed with this news.