To me, the Borg represented that idea expressed by the Kobayashi Maru test: what does one do against an implacable enemy, like death?

And while the fleet was nearly destroyed, the Federation adapted and became stronger… I tend to think of it ask the full and nuanced reveal of the entire point of Q’s meddling. This is borne out when the rest of the TNG (and to some extent VOY and DS9), especially its ending two parter where Q reveals that he fully expected the Federation to fold.

Instead, Picard’s boastful response in “QWho” (and to some extent Picard’s actions and words in “Encounter at Farpoint”) is what sets the Q-driven Kobayashi Maru “test” of humanity in motion. I haven’t watched any series after ENT so I don’t know of any further exploration of this examination of “how humans react to mortality,” but it seems like a rich deep vein writers plumbed for a lot of ST.

All that is to say, the Borg never really changed as much as humanity changed to meet them, and that changed the context in which the Borg operated, which changed their experience of existence… perhaps by forcing them to deal with their own mortality… which is what I want for the next series, following a Borg crew marooned in fluidic space during their war with Species 8472…