And why keep arming personal who are going to be faceing the Borg with easy to adapt to phasers and energy weapons when they seem pefectly vulnrable to projectile weapons and melee weapons! Come on how hard would it be to replicate a AK-47 and a longsword!
The Borg would just adapt their shields to reflect bullets. We've seen ships bounce of the Ent_D shields.
If they could adapt to bullets they would have done so already. After assimililating thousands of species and trillions of life forms they would have encounterd projectile weapons and if they could have adapted to them they would have.
It seem like a weakness to exploit