Hindsight being 20/20, the Avengers needed a female founder. but did they, ultimately, need another clean shaven blonde male? Henry Pym's a fine character. but his contribution to the mythos is all science related. all they needed was a scientist to create a way for people and objects to change size. even Jan could have been introduced as a scientist and retained her flirty personality. but, back then, it would have been seen as unrealistic. she needed a male chaperone, for lack of a better description.
sooo, why not Vernon? he considered Hank to be a peer. he found a way to breach the Kosmos Dimension; where Pym particles are as plentiful as air. there's nothing stopping her from being Giant-Woman for the founding avengers photos. worked for Rita Farr. i bet she would have gotten a solo title, by now. they could have sold her as an answer to Batman; being wealthy, solving crimes, and kicking butt. what's your opinion on it?
p.s. in the interest of equality, I'd write out Scott Lang as well. Cassie could be introduced as a very young cousin of Jan (at some point). she already kind of acts like a spoiled rich girl.