Actually I think that might've been introduced in First Contact not on Voyager.
No, I'm pretty sure it was first expressed in the Voyager
episode, "The Omega Directive". Where First Contact
stumbled was in the introduction of a Borg Queen to give the drones a dramatic focus and a face. Both were bad ideas that undermined the novelty of the Borg concept.
"We used to be exactly like them. Flawed. Weak. Organic. But we evolved to include the synthetic. Now we use both to attain perfection.
" -The Borg Queen, First Contact
Oh come off it, that was a line with no meat at all relevant to the rest of the movie's story. She could just as easily have used words like destiny, beauty, ascension, or a dozen other nouns that would have made no difference at all to any of the characters or plot in First Contact
. Do you honestly think someone was sitting behind that script thinking, "Gee, let's make the Borg motivated by a zealous pursuit of perfection?" And yet that's exactly what came out of "The Omega Directive". That
's where the show's writers deluded themselves into thinking that would make a good motivation for the Borg.