You're right, pathology is an easy match, and your grades aren't all that important.
But... you should still put some effort into your 3rd year rotations! The best pathologists are those who have a solid clinical groundwork. As a pathologist, you will need to know the indications for a biopsy or surgery (i.e. sources of specimens), and you will need to know how they present clinically. When you're sitting at signout, your requisition will have a clinical impression on it. Your diagnoses are more likely to be on target if you know enough clinical medicine to understand the rationale for why slices of the specimen are in front of you. Furthermore, if you're at all interested in academia, you will undoubtedly take part in translational research (not only because it's interesting, but because your grants will be funded and your manuscripts published). Ignorance of clinical medicine will hurt you as a pathologist.
I thought about path for a long time (changed my mind, currently applying in rads...) -- pathology is a fantastic field that needs smart people. Go for it!
Best,
doepug (MS IV)