That sounds about right...Is this true? The way I have come to view introverted vs extroverted functions is that introverted ones are more mysterious to the outside observer. It's happening on the inside and is unique to the individual using it, so people have a hard time understanding. That doesn't mean it's more complex, just more mysterious and less apparent.
Also, introverted functions tend to be more linear. This is probably largely because of the rapidly changing nature of the external world when compared to ones internal thoughts. We can much better control the diversions that take place in our heads than we can all the new stimuli we're constantly bombarded with on the outside. That makes extroverted functions quicker, farther reaching in multiple directions, and their complexity is found in the sheer amount of different factors and options it can hold and process at a given time. Their divergent, far-reaching energy shouldn't be interpreted as simplicity.
This leads into introverted functions being more linear. They're able to build upon one or a few choice tracks of thought over long periods of time. They're slower moving, more concentrated energy. Sure, maybe over time, there's a point at which an introverted function has been pruned and developed for so long that it surpasses the extroverted functions' capacity for information held at a given time, but for the most part, I'd argue that it's the linear, concentrated nature of introverted functions paired with their somewhat hidden nature that makes them seem more complex.