I'd also like to add that this ties into what's good about Lost Souls. The Borg as cybernetic zombies is dealt with in a respectful manner. The Borg, like the Daleks, are treated both seriously in their concept (they are a race of "pure evil" because they're each without free will) but that destruction of them is evil in itself.
J.R.R Tolkien, frequently accused of being a racist in his own life, was actually troubled by the concept of "purely evil" Orcs as they were the first real race of note created solely to be cannon fodder for our heroes to effortlessly cut down. He was aware of the troubling consequences of this as it conflicted with his Catholic faith and, in all likelihood, reminded him of the kinds of arguments he heard in the 1940s.
Star Trek created one of the best "cannon fodder" races in the Borg for these fantasy ethical discussions and the best use of the Borg after BOBW was the merciless deconstruction of this. "Hugh" showed the Borg who grew up in the Collective were not evil or malicious (like the Founders) but simply mislead as to the nature of their situation. Seven of Nine ran with this premise and the "Cooperative" indicates that without the merciless driving will of the Queen, the Borg might actually be something people could willingly join.
Star Trek Destiny is all about the redemption of the Borg and the Caeliar is a necessary deconstruction of their role as absolute evil. It's a tight balance to walk but addresses the issue of universal slavery, "innate evil", redemption, and so on without failing. That's probably the biggest accomplishment of Lost Souls.
It nicely says, "No, Picard was RIGHT not to kill the Collective. He might have saved sixty billion but he'd have killed trillions."