The Conlang mailing list is dedicated to the discussion of the construction of artificial languages. And Rosta for starting the discussion. The design of a comprehensive yet simple anaphoric system is not especially difficult.
All natural languages have one.
However, as is typical of natural languages, the anaphoric systems are clouded in idiosyncrasy and irregularity. One of the problems that many people have is that they tend to think of anaphora as belonging to a special, closed class of words. William Shakespeare lived in a small town with his pet rock and his wife Fifi Yokohama. He would not eat veggies, she would not eat vegemite, and IT didn't eat at all. John said he'll definitely attend the class on Creative Suffering.