The Canadians were the first to breach the German Wall at any point ... unfortunately, having accomplished this they didn't follow up by pouring men and equipment thru the breach and wrapping around to both the north and south and attacking the Germans from the rear. This tactic, had it been employed, could have easily collapsed the German line in both directions for at least fifty miles.
Yes, I am curious why Currie or other commanders neglected this point and simply reinforced Vimy. It would have been an ideal moment for a counter offensive.