That would essentially be turning back the borders approximately 100 years, to the point where northern Manitoba, Ontario, and Quebec were part of the territories. Although that would have just been the Patricia region of Ontario (not all of NO).

For the most part the Northern parts of Ontario are treated differently... they're not "territories" though, they're "districts". Districts are a bit different than counties... for one thing, they are almost entirely made up of Unorganized Areas.