Voy-Haters who keep saying Voyager ruined the Borg. There being a single species out there that could fight the Borg and win in a normal fight is where they keep saying the Borg lost all threat whatsoever.
That these creatures were super-powerful aliens from another dimension didn't matter to them, they had such ridiculous ideas of the Borg being some super-duper-threat (they are not) that there being ONE species out there that could fight them totally destroyed their image.
Worse, since it was VOY that created these new aliens, it was just another mark against the show. If it had been TNG or DS9 that created the 8472 aliens no one would care, but since it was VOY it was just another thing to "blame" the show for.