Is perfectionism necessary, in regards to grades? I hope not. I don't have a stellar academic record, and I know a lot of premeds who didn't either. But they're just grades, and we all know there are a lot of reasons why they're not necessarily accurate -- illness, family problems, trying a new subject, extracurriculars, etc.
But to aspire to excellence? Sure. I think an important aspect of medicine is that we continually re-examine the world in which we live and the health threats we face. No one is perfect (and, in fact, believing that you're near-perfect can really hurt you when you realize that it's impossible to be a perfect physician, or spend as much time as you should with each patient, etc.), but keeping things in perspective and aspiring to do our best is what we should aim for.
🙂 🙂