That's one way to look at it. If political parties were to be regionally centralized, then it would simply be a matter of the ratio of the percentage of each city voting that would indicate any kind of "spillover". Mind you, your example may paint a bit of a false picture, as this spillover effect will actually be distributed across all candian cities, at a very marginal rate. Not only that, but the representatives for that area, would still come from that area. Again, I still think what you point out is a valid issue, just not the extent that may be gleamed from an off-hand "extra MPs in Alberta because you killed it in downtown Toronto"
Ultimately the outcome is the same though, the party that runs up big wins in noncompetitive regions gets rewarded with extra MPs. Urban areas with many ridings are going dwarf rural areas even more when it comes to representation in the house. I like our system of regional representation. I'm untroubled that somebody commands a majority without having to have 50+% of the vote - I see that as a necessary trade off between having three major parties and having stable Governments.
Stability and the ability to execute a mandate are, to me, more important than precise representation. People are much more frustrated with a Government that is incapable of doing anything than a Government that does the wrong thing (when it comes to representative systems).
There is a very strong argument however, for ensuring the party ideology which gets elected is what in proportion to what the people want. If a society votes 60% a and 40% b, you should want the government to be as close to 60% a and 40% b as possible. If the level of variance is such that b can actually hold power in this situation, that may be a much more valid concern given the relative merits of both voting systems.
That's a pretty different scenario in Canada though, isn't it? A person voting Liberal in BC and a person voting Liberal in NB aren't really voting for the same thing. We don't have parties that go "all the way down the stack" except for the NDP (and that's not really working out tremendously right now). Provincial and Federal parties are in most cases at odds with each other even when they're technically on the "same team", and we don't even have political parties at the municipal level. I personally don't think the political system in Canada would benefit tremendously from PR, I really don't. Obviously that's just one jerks opinion.
The NDP doesn't care what form of Proportional Representation wins out as long as its a form of Proportional Representation. Yes they campaign with and show a preference for MMP, but if STV was put on the table they would jump on it immediately because their main priority is Proportionality.
If we're talking realpolitik, the NDP should have known that PR would be a non-starter in the committee. They swung for the fences and whiffed. Had they thrown their weight behind something like STV we would be having a different conversation. Rather than make them an offer that was difficult to refuse, they made one that was easy to reject.
Nobody is proposing this. The forms of Proportional Representation being proposed is to do it proportionally using each provinces vote. Eg. Ontario Votes are only proportional within Ontario, Alberta Votes are only proportional within Alberta.
I admit I phrased that poorly, I think my answer above more or less covers what I meant by that.
A heavy supermajority of First World Democracies utilize a form of Proportional Representation and while Fringe parties are within their parliaments in small numbers, they never are given a chance to govern because the governing coalitions coalition with the other sane parties which hold more seats.
Seems like an expensive exercise in making people feel good? If fringe parties can never matter than what are we really losing by not including them? I don't really want to pay for Jhonny Racists pension because he managed to pick up 3% of 45 ridings. I realize you can set limits to how much support someone has to get before they qualify, but again why?
I've harped on this before, but I'm also deeply uncomfortable with giving MP jobs to people who either didn't win one (and thus were rejected by the electorate they stood in front of), or didn't try to win one. That's just me, but I can't see any way these 'extra MPs' aren't just also-rans and party cronies.
Given what Rob Ford was, this will never not be a dumb comparison pretending that he was even in the same ballpark as the malice and stupidity that Trump governs with
Stop the Gravy Train and a subway to nowhere isn't super different than #MAGA and build a wall. Ford wasn't able to do anything in his mandate after his first year. We'll see how Donald fairs, but my suspicion is similarly.