1.) That was my thought, and another good reason to consider it an increase in the weapon's base damage.
2.) Spycraft does half actions and actions instead of standard, move and full-round actions. You can only attack once per half-action, and you can spend both half-actions to make two attacks. Spycraft predates True20 and Saga Edition in its removal of iterative attacks.
3.) For me, I'm giving the same basic functionality to Power Attack, to make it easier on players. Take a -2 on the attack, get an extra die of damage. Simple, and no major numbers to keep track of.