The OED lists many senses for empiric, as both noun and adjective, but almost all of them are labeled as rare, obsolete or historical. As far as I can see the main current use of empiric is in specialist medical writings, as an adjective for medical treatments based solely on empirical results, where the reason for the treatment's effectiveness is unknown or uncertain. E.g. "empiric antibiotic therapy".
In more general contexts, empirical is used vastly more often than empiric. I think empiric should certainly remain in the rare category.
What about empiricist? It's certainly not as common as empirical. And like empiric, it is often found in academic publications. However, while empiric is almost always used in medical journals, empiricist, as both noun and adjective, appears in a great variety of scholarly writings, including publications dedicated to psychology, philosophy, political science, literature, legal studies, physics, etc. I even found the word in the Journal of Sex Research.
Is empiricist a word Chi players would probably know? Maybe it's a bit borderline, but I'm leaning these days to the view that things may as well be left as they are unless there seems to be a compelling reason to change. So I'm not satisfied empiricist should change from its common classification.