It may be useful to consider electoral reforms with less than full proportionality, as a compromise or step in the right direction.
For example, the “MMP-lite” (or “Limited MMP”) model designed by the Jenkins Commission in the UK was specifically intended to increase the odds on stable governments, while getting many of the benefits of a mixed member proportional model.
Another option is the parallel system, once used in Russia, still used in Japan.
The Pépin-Robarts Task Force on Canadian Unity in 1979 recommended:
i. The number of members in the House of Commons should be increased by about 60.
ii. These members should be selected from provincial lists of candidates prepared by the federal parties in advance of a general election, with the seats being distributed between parties on the basis of percentages of popular votes.
That's the parallel model, because those extra 60 MPs do not compensate for disproportionate local results. Rather than the "top-up" Mixed Member Proportional model, they are a separate, parallel, election.
On the votes cast in 2008, the additional 60 MPs would have been 21 Conservatives, 18 Liberals, 12 NDP, 6 Bloc, and 3 Greens.
This model would have addressed regional divisiveness slightly by electing 22 more MPs from provinces where their party’s voters were underrepresented: 1 Liberal MP from Alberta, 1 more from BC, 1 more from Manitoba, and 4 more from Quebec; 3 more Conservative MPs from Quebec; 4 more NDP MPs from Ontario, 2 more from Quebec, 1 from Saskatchewan, 1 more from Alberta, and 1 more from Nova Scotia; and 2 Green Party MPs from Ontario and 1 from BC.
But it would also have elected 35 more MPs from provinces where their party’s voters were already over-represented: 8 more Conservative MPs from Ontario, 3 more from Alberta, 3 more from BC, 2 more from Saskatchewan, 1 more from Manitoba, and 1 more from New Brunswick; 7 more Liberal MPs from Ontario, 1 more from Newfoundland, 1 more from Nova Scotia, and 1 more from PEI; 6 more Bloc MPs from Quebec; and 1 more NDP MP from Manitoba. Along with one more Liberal MP from New Brunswick where Liberal voters were already fairly represented, and two more NDP MPs from BC where NDP voters were already fairly represented.
I doubt the public would want 60 more MPs when more than half of them would just add to a party’s over-represented strongholds. But if we cut the local MPs to 248, so each riding is 25% bigger than today, doesn’t the loss outweigh the gain?
And the Pepin-Robarts model used closed province-wide lists, not the open regional lists that Canadian voters are likely to require. As Jenkins said, additional members locally anchored to small areas are “more easily assimilable into the political culture and indeed the Parliamentary system than would be a flock of unattached birds clouding the sky and wheeling under central party directions.”
No, if you want a compromise with 247 local MPs and only 61 regional MPs, go to a Limited Mixed Member Proportional model.
That model is a compromise toward the model recommended by the Law Commission of Canada.