I don't think that Sandra is necessarily pro Canadian in her commentary. I think she favors a particular style of skating and choreography. She has been very plain about that over the years. She is a purist in many ways and while she appreciates innovation (for example Lambiel or Takahashi) she usually prefers it to be part of a cohesive whole rather than for its own sake. Don't get me wrong, I have my disagreements with her on many things, but I think she is pretty fair as far as national bias most of the time. Also, many of the top skaters from the around the world are going to Lori Nichol and David Wilson to create programs at the moment, not just North Americans.
Also consider that she is just as well known for the programs she choreographed for non-Canadians (Boitano, Yamaguchi, Chen, Lipinski) I would say she has a fairly open-minded perspective.