Well, my personal opinion is that having the Borg in a "normal" Star Trek game as a player race, just doesn´t work. These guys are supposed to be a million year old civ with the assimilation knowledge of countless other civs.
Having the Cube appear like just another Space Monster, would´ve made more sense.
Birth of the Federation, played that nicely. Once the cube appeared you better take you´re WHOLE fleet to meet it, and pray for it going down WITH 90% of your fleet.
The only way a Borg race makes sense, is if they would be the surviving Drones of a crashed and disconnected Borg ship. Or in a 27th(?) century(Voyager final Ep) scenario.
Just my 2 cents.