If anything, Extraverted Sensing is the function that makes one inflexible, especially if the person has a painful Extraverted Intution and does not consider other alternatives. Those with dominant Extraverted Sensing will percieve the ONE way that they want to do things, and pursue it with the help of thier secondary "analyzing" function. This will make them seem somewhat inflexible and kind of like a "J" type.
I agree with your j/p idea. However, with what you said about the
inflexibility thing, it's not always quite like that. Having a strong
myself, I'm flexable if it has to do with the situation at hand. For example, if the car breaks down, I'll be very open to new ideas to get the thing fixed, and I won't explode if my plans are wrecked. I'm really open to trying new experiences, and tend to not back down just because it's "new." Maybe I've just developed my
, but from what I've seen, most of the ESxp's I've seen are really flexible.