Charles Trip Tucker III said:
If the Borg wanted to put an end to the Federation so badly that they were willing to whipe it from history... why not just send a fleet of 10 Cubes? I guess when the movie was concieved, they hadn't thought out the Borg Collective being as large as it was presented on VOY.
Less is more in this case.
Seeing an entire fleet including the Mellenium Falcon take on 1 cube and getting their asses handed to them demonstrates the power of the Borg, 10 cubes and wed expect nothing less than the fleet receiving their asses on a silver platter.