It disappoints me that I couldn't find a way to include them, since part of my goal in GTTS was to tie off all the remaining loose threads about the Borg before Destiny brought their story to a definitive end.
Christopher, whatever makes you think
Destiny represents "a definitive end" to the Borg?
Outside the box, that may be the intention of Margaret, Marco, and Dave in creating
Destiny, and Margaret as a "producer" of
Star Trek certainly has great latitude to see that vision through, but she's not going to be around forever. Your sentence would be more accurate to say that
Destiny represents "a definitive end for the Borg, at the present time, insofar as Pocket Books in concerned."
A different producer -- whether in Paramount's studio offices, IDW's offices, or even in the hallowed halls of Pocket Books itself with -- may well decide to take the Borg toy off the shelf and play with. In the world of
Doctor Who, how many final ends have the Daleks seen, for instance? Even if I were to imagine Patrick Troughton standing on the Borg homeworld watching as the Caeliar atomise the planet, muttering about "it's the final end," a different production team, different writers with a story can so easily overturn what
Destiny did.
Inside the box, I can easily think of a half dozen ways the ending of
Destiny can be undone.
The simplest is taking
Homecoming to its logical conclusion -- if the Federation has the knowledge to create a Borg Collective, that knowledge can be used to nefarious ends.
Then you get into time travel and alternate universes.
And I suspect that the Borg in
Alien Spotlight: Borg originate from a post-
Destiny timeframe.
I won't say there's wiggle room built into
Destiny. I'd agree with you that
Destiny was
intended as a "definitive end." (The revelation about Picard no longer hearing the Collective at the end is striking.) And for right now, it is a definitive end.
But that won't always be true.