First things first. I think we have to distinguish between what some people might call descriptive representation, meaning people like women and minorities and such in the House, and for lack of a better term, substantive representation, meaning that the views of minorities and women and such are better represented in policy and decision-making.
That also tends to get to this issue of fairness. When we talk about wasted votes, we should really distinguish between input fairness and output fairness. Canada has input fairness—nobody disputes that; every vote is counted fairly—but output fairness is that every vote counts fairly. I would say any system that provides equal voice for votes is going to provide greater diversity of substantive representation in our political system.
One comment we do get for SMDPR is whether there is a risk that it won't provide descriptive representation in that you're still running in the local ridings in the same way. I think there are two counter-arguments to that, which do seem a little counterintuitive. One is that by incentivizing parties to reach out at the local level no matter how well they've done in the past—you've always had an incentive to improve your voter percentage—you have to reach out to a broad range of groups, so you might want a candidate who is more diverse. I know Tony Hodgson used the male, pale, and stale line.