I honestly thought bringing back the Borg from their apparent demise in Endgame was a really bad change to the status quo, which only got worse with the Supercube/invasion nonsense.
"Endgame" never alleged that the Borg had been wiped out completely, just that a severe blow had been struck against them. Their transwarp network had been trashed, impeding their ability to reach the Federation, and their Unicomplex had been infected and destroyed, but we saw that the Borg sphere pursuing Voyager
was not affected by the same pathogen, thus we could assume that the many other Borg cubes and planets that we already knew were scattered across much of the galaxy survived as well. Their command and transport structures were crippled, but "Endgame" was certainly not an act of genocide -- which would've been a pretty hideous climax for a Star Trek