That's a good set of questions.
First of all, I would slightly object to the original characterization of making seats match votes on a party basis. That's not really what we're talking about. I'm reminded of that joke about gravity: it's not just a good idea, it's the law. This is what our charter is. Our charter says that each citizen is entitled to effective representation, and it really doesn't say anything at all about parties. That's a symptom of the mismatch that comes from an absence of representation.
In the ideal world, if you take all the voters and divide by the number of MPs—we have about 50,000 votes per MP—what should happen, in our view, for each citizen to be represented is for them to be able to elect their MP over however large a region is necessary for that to happen. If I'm in an area in northern Alberta where there's 70% support, I need one and a half current ridings to get my 50,000 votes. If I'm a Green Party candidate in Vancouver, I need about 10 ridings right now to get that support.
I think we need to honour that as much as possible, and in my view, STV does the best of job of that, the mutli-member districts.