We have had this discusion twice, both times it came down to 'yes they are vulnerable, yes Stafleet are idiots'.I wonder if projectile weapons would always be effective against Borg drones... I also wonder why Starfleet ships don't keep small stockpiles around in case their phasers are ineffective. I can't think of many situations in which this would happen, but still...
Here is the main one. Beware, its long!
And, as always, we ended up talking about something completely different in the end.