The simple truth is that Hero is a game for and by high-IQ people. It sounds elitist, but I'm convinced that is the case. People with IQs below 100 struggle to grasp key concepts and usually hate it, those at around 100-120 can learn it, but need to be guided or particularly motivated to get over the hump, and over 120 IQ folks pick it up easily, and tend to be the ones who love its possibilities.
I gave the 6e rules to one of the smartest guys I know, who is not even a gamer, and he digested it over a weekend and was totally enthused. It was quite eye-opening. I'd put his IQ at 140-150.