I see what you mean.
My thinking is that introverted feeling acts as a governor on extraverted sensation, preventing you from going too far with it. Maybe even preventing you from getting the most out of yourself.
You run into problems when you go too far in the introverted direction. Which is the more natural thing to do as our dominant function is introverted.
ISFP Personal Growth
I agree with this page that the key to unlocking the potential of an ISFP is in developing extraverted sensation.
What do you guys think?