The trick is getting a good story out of that. Entities like that are like Mars in A Miracle of Science: they’re something to be wondered at rather than a primary protagonist or antagonist. There could be good dramatic tension when a loved one joins the collective while a main character doesn’t, and interesting exposition when you have a Borg on your bridge crew (providing an alien contrast to highlight the human condition), but Federation vs. Borg is just silly: the Borg have no need of already-habitable planets and very little reason for major conflict with the Federation. Now, there could be some really interesting stories if you were to have the Borg defending the Federation from the immature nittishness of the Q Continuum and Federation heroes being able to make the difference in a standoff between an up-and-coming collective intelligence and a decadent ascended civilization...