Just a random thought I have been mulling over.
Ne makes you look eternally outward and become absorbed in the external object.
So imagine in both cases with a dominant Ne, you look to the external world for continual affirmation, either intellectually (Ti) or emotionally (Fi).
For a healthy individual you strengthen the tertiary function and at some point become more self sufficient and stronger and able to be less sensitive to either critisism of your intellectual ideas (Ti) or rejection of your emotional advances (Fi). You become less dependent upon external affirmation of your self worth.
For an unhealthy individual you never develop that tertiary skill and end up profoundly dependent upon Ti/Fi always searching for external confirmation through Ne.
ENTP=Compensetory Narcissistic personality disorder and a lack of Fe, hypersensitive to critisism of thier ideas/they become thier ideas
ENFP=Borderline Personality Disorder and a lack of Te, hypersenstive to rejection of Fi
Both are marked by extreme withdrawal upon any perceived rejection/criticism, being very difficult to "fix", and feelings of hollow, empty nothingness given the lack of an internal compass.
Seems like development of Ni might be the real solution to balance that crazy fucked up Ne.