I feel and I hope the Devs agree that three attack powers in the Ninja set are outdated and underwhelming. Let's look at the other mastermind power sets:
Beast Mastery - Summon beast to attack your enemies, that checks out.
Demon Summoning - Use a fire whip, my favorite and also the demonling uses a similar power.
Mercenaries - Rifle which is also used by your pets.
Necromancy - Dark blast which is also used by the Grave Knight.
Robotics - Pulse Rifle while the pets use a similar weapon.
Thugs - Dual Wield which is also used by your pets.
Ninja - Arrows? What? None of the ninjas use arrows.
Also all of the other mastermind sets attack powers come with a secondary effect (knockback, -ToHit, damage over time, etc) while Arrows have none. I mean they could have at least given us an explosive arrow.
I would like to know if the Arrows can be switched out for Shurikens, that would make so much more sense. Your pets use shurikens and the powers already exist in the game. Dominators get Shuriken Throw, Trick Shot and Explosive Shuriken in the Martial Assault power set.