They VOY should've had cannon fodder, instead of just being alone. Of course giving them cannon fodder would violate the premise of the show.
So they did the other logical thing and had there be other species out there as tough as the Borg.
And how did the audience react? They though that since there were other species out there as tough as the Borg the Borg were now irrevocably ruined.
And naturally, if "Scorpion" had been a TNG or DS9 episode, no one would care.
You just can't win.