yeah, perception is all about examining the outer world, which includes oneself. inner pictures of ni are representations of the world. there is only one world. only one brain. only one skull. communication takes place inside of it. gets something going. creates resonance. is inspiring.
introversion is about "creative" uniting of as much as possible and examining the intrinsic character of one such united entity, extroversion is about "objective" fragmenting/dividing of the whole into virtual entities and examining the interactive (external) character of those fragments. both get a big picture of everything, just the boundaries are defined differently, and the prediction of the character of the whole is sort of "sidewards"
introverted perception grows with experience, but fears to be totally overwhelmed. extroverted perceptions copes with volume of experience by becoming more superficial, remaining very effective, but getting nihilistic.
Yes, it seems that all E functions are more effective at first, and all the I functions grow with experience. Fine example is Se and Si. If you had enough memory of something, there would be no need to perceive it from its source. Although I think Si is aimed towards what some one is used to and not so much the probability that it happens. So Si wouldn't necessarily try to perceive the result, but rather know if something is normal or not.
This leads to the fact that Ni seems to generalize its past sources into a single concept, and that's why I think it is less biased compared to influence of possibly one or two external factors (extroverted function).
Disagreement
Ne=A can easily lead to Z
Ni=no it can't because A is very similar to B, and B has always been B (something going on in the unconscious)
Ti or Fi starts out with too high of standards in which most ideas aren't going to be accepted. The INXP could just improve on the idea, but in most cases they keep surfing ideas because none of them seem to be fitting their J function. The reason why Pi cannot be perfected is because it is unchanged. It is like fitting a color blob to custom lines. How long is it going to take you to find the perfect outline? When you find it, the color is structured by the lines, but the lines don't exactly form a powerful shape like the square or triangle. But it can.
Ni contains a very specific idea applying to Je. The idea of Ni must fit the correct standard of either Te or Fe, so the idea or vision must morph into that reality, into something that can be accepted, by us (the user) and everyone else. That is why Ni users question their vision, because it is correct, but it never fits with their specific idea applying to Je.