I interviewed with, and was accepted to, Rotman back in March. I spoke with a woman named Claire from admissions, and she was wonderfully pleasant. The questions I was asked were typical ones, but framed in such a way as to bring out my experiences. Example questions included: Why an MBA now...Why Rotman...How do you envision your life unfolding after the MBA experience...What valuable contribution will you be able to make to the program, etc. The interview was highly conversational, and I never felt as though it was a formal interview. Absolutely none of the questions were case style ones, nor was I asked about my knowledge of potential career fields, industries, etc.
Quite literally, the best way to prepare for the Rotman interview is to read-up on their website literature so that you can ask them some knowledgeable questions. In my case, the interview was not designed to test my knowledge of anything -- it was, instead, a get-to-know-you conversation. It's one of those interviews for which the best advice is: just be yourself