Ultron is a important aspect of Pym history, but no way a huge part of it. I mean Pym himself only encounters Ultron a handful of times Ultron has shown up. Hell for all we know Stark might be tinkering with an abandoned Pym project and starts the whole thing.
Folks need to get on Pym he is so much more then a wife beater and the guy who created Ultron.
The fact that this movie will be introducing Scott and (possibly) Hope as Ant-Man and Wasp in the MCU is my biggest gripe with it just because I consider Hank and Janet great characters. I'm also actually more disappointed that Yellowjacket has been removed from Pym rather than his involvement with Ultron.