I agree that overuse of "it" is very confusing and in both the written word and in speech. Overuse of "it" is often a sign that the writer or speaker is not fully clear on the topic in their own mind.

On the other hand, "under use" of "it" can also lend friction to understanding as "under use" of "it" destroys briefness. Cognitive load increases as we wade through "under use" of "it" again and again.

A little bit of it is good. Too much of it is bad.