Originally Posted by Rock Sexton
The problem they face is they already have a character with an advanced AI system. From a story-telling standpoint, to introduce another one in the MCU would be recycling.
Stark and Pym are two very different types of scientists. Stark is all about hardware, while Pym is more of a biochemist. I'd link his Pym Particles to a biotech form of nanotechnology that he develops after studying insects and microorganisms. And then make Ultron from that --- have him be more of a biotech construct than a nuts-and-bolts walking tin can.