The relocation of Saskatoon's CN station to a remote area was one of several station projects financed as "modernizations" by the federal government in the 1960's. As I recall, the Ottawa and Hull and Quebec City moves were in the same program. (For newcomers, there have been projects to ameliorate the issues in Ottawa and Quebec City. For Saskatoon, most of their service is gone.)
The Edmonton relocation was to open up the CP and CN yard area for developments and to "solve" the purported downtown parking problem. It also saved replacing the 105th Street viaduct and the 109th Street "rathole" underpass. The new location is on a someday rapid transit route, thereby salving the consciences of people who knew better but said nothing.
The Phoenix situation is different but it has the same end result.