B
Can somebody seriously explain why Superman is a Sensor? Having excellent reaction time and physical fitness does not make you S, especially if you're a superhero. And let's not get into "the American way". The popular conception of this has little in common with the founding values of America.
(It is an aside, but I agree with those who have said they find Superman less complex and inspiring a character as, say, Batman.)
For starters, Superman really enjoys the staus quo. He longs for the simple life. He is a simple man cursed to be different from the society he admires so much. He is the model ISxJ. That said, he avoids conflict if he can so that makes him a little bit like a feeler, though he will fight to defend others and to keep earth safe. He personally does not have much of an ego. This points strongly to ISFJ.
Batman is more of a IxTJ. Maybe ISTJ since he does not entertain ideas with no practical use, though I could see INTJ for him due to his highly eclectic knowlege base (this is not a strong argument for INTJ.)
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xNFP heroes are going to be gentle creative types with a need to understand everything. They are going to avoid fighting as much as possible, but will hold dear values such as Truth or Compassion that can place them in a hero role.
xNTP heroes are going to be anti-heroes, as a given rule of thumb. There are exceptions like Mcgyver, though.
xSxP heroes are going to be very literal, and will have a special disdain for villains who "kill their friends over a peice of paper."
xSxJ heroes keep life as simple as they can, only coming out when the status quo is challenged.
xNxJ heroes try to change the environment to a vision they have in mind, either endless thinking of improvements to the global system or by actively working towards that vision. This is were Superman falls short. Even when he was on Bizarro World, he did not try to change their ways, but instead was focused on maintaining harmony and getting the heck out of there.