I wouldn’t really say that Sue was as much of an incompetent ditz in the 60s as some people may make her out to be. Stan Lee and Jack Kirby could make her competent when they just focused on that and tried, like in Fantastic Four #60 (March, 1967):
So yes, if they could display competence for Sue, then the same could be done for Jan, and it’s not all about blasting everything with cannon-levels of power either.