The ER committee laid out options for the Government and made the following recommendation:
Recommendation 1
The Committee recommends that the Government should, as it develops a new electoral system, use the Gallagher index in order to minimize the level of distortion between the popular will of the electorate and the resultant seat allocations in Parliament. > The Government should seek to design a system that achieves a Gallagher score of 5 or less.
Recommendation 2
The Committee recommends that, although systems of pure party lists can achieve a Gallagher score of 5 or less, they should not be considered by the Government as such systems sever the connection between voters and their MP.
That means that STV (which is multi-member ranked-ballot with large ridings), MMP (local ridings with a regional proportional fallback), and the urban-rural hybrid (cities get STV, rural areas get MMP) were all on the table as options. The Liberals just flipped the chessboard because the committee didn't recommend their preferred ranked-ballot-instant-runoff-single-member system.
Open-list MMP with ~12-member regions would be an excellent solution for Canada.