Garlonuss

Chosen answer: One Borg ship is usually enough. You notice, they were only able to destroy it because their assimilation of Picard ended up giving his crew a unique 'backdoor' into their system. No one had ever tried to retrieve an assimilated crewman before, because it is usually such a futile effort. So if the Borg feel that one ship is enough, they will send one ship. They are big on efficiency. Sending more ships diverts ships away from other potential targets and missions.

Garlonuss