How important is a public speaking course for Pre-med schools? Irrelevant? Small Bonus? Recommended?
Depends what you mean by "important", how good you are at public speaking already, and what level of schooling you are at.
In my experience, here is the public speaking components of med school:
1) On clinical rotations, expect to present patients' H&Ps to attendings and groups of residents multiple times a day. Sometimes your audience will be hostile.
2) If you attend a PBL med school, expect to give regular presentations on assorted medical topics and clinical problems. Your grade may hinge on your ability to deliver these well.
3) During your MSIV year, as you frantically compete for spots in residency programs, a well-rehearsed & intelligent talk on a clinical topic will go a long way to getting you in.
If these are things you think you will be comfortable with, no need to take any formal training. But if you are one of those people whose mind blanks and starts to feel woozy at the thought of speaking in front of people, it might do you some good.