I guess so. The existing system under-represents very small regional parties and overrepresents big regional parties. That's why the Bloc at times were overrepresented and at other times under-represented. The existing system is not biased in any way, I think, in general for or against regional parties. PR would not change that.
What would change that, I think, as you mentioned, is that the Liberals, for instance, would much more easily elect some MPs under PR in Alberta. So the differences in representation of different regions within parties would be smaller.