I don't see the competitiveness/dominance/need-to-be-center-stage of the ESTP as being Sheppard traits at all, though. He's pretty clearly not a guy who cares about winning -- doesn't mind being bested by Teyla and Ronon at physical activity, or McKay at mental stuff -- and doesn't want to be in charge (First Strike). Most of his leisure activities that we've seen in the show (reading, surfing, sudoku, jogging) are solitary things, and he claimed to be content flying helicopters in Antarctica, about as solitary and non-competitive as you can get. I'll certainly concede that he's more focused on the phsyical world than what's going on his head, but he's not in any way a *social* extrovert.