The long-haul North American award can be quite valuable if it includes segments on First Air in the north. First Air flights are usually very expensive.
This summer I am flying Miami to Yellowknife. Total miles: 3550 each way (same as Toronto-London). Cost of a restricted seat sale ticket in economy: $1150. Aeroplan points required: 25,000, or the same as Miami to Toronto.
The award would be even more valuable if I were flying to some place like Inuvik or Resolute.