I spent some time with a wizened, bisexual ENFP last night, and I think I have a grasp of what Fi is now.
He challenged me to contemplate my nonexistance, and that fact that I could not do so, despite the fact that I could not express why, is undoubtedly the essence of Fi. In fact, even Ayn Rand's axiom of "Existence exists" made sense from that perspective. It could probably even be argued that Fi is a different play on Rene Descartes. "I feel, therefore I am."
He then argued that his life is about his choices and anyone else's choices are incircumstantial. but he explained that does not negate that he cares about people or the choices they make, only that other's choices are irrelevant to his existence. The most important thing to him is his choices, because he believes they dictate his happiness. From an Fe perspective, that seems somehow cold, but from a Ti perspective, it seems incredibly realistic.
I can see why Fi users would consider Fe to be superficial by comparison. Fi is integrated at the core of a person's existence, and everything that is and ever will be of that person, as well as any choice a person ever makes in his or her life, is derived into the essence of Fi. It is feeling of indescribable depth, beyond reason or consideration because it is found entirely within the indisputable existence of the individual. What is observed as "egocentric" by the Fe, is actually feeling which is derived from the actual awareness of self. In fact, I can't think of a better way of describing the two...
Fi= feeling derived from consciousness of self
Fe=feeling derived from consciousness of others
That isn't to say that Fi isn't aware of others, but only that it is aware of others through its awareness of self. Which makes sense to me since I conceive my awareness of self through my awareness of others. Or in other words, how I percieve others percieve me, provides my perception of myself.
I can't really decide which would be superior to the other since they are so fundamentally different. If you are talking about identity, as in the character and attributes that are composed and asserted from a person's very entity, then Fi is superior. If you are talking about interdependence, as in how everything and everyone is connected and how those bonds are nurtured through self control and dedication to ideals, then Fe is superior.