Why does it cost so much stamina to do a deflect with Shinobi? There is no reason to go for deflect over a parry on most assassins ( don't have much experience playing with Zerker so I don't know how it is with him). Deflect should be a viable option like a parry and not just a flashy thing to do. Deflecting with a Shinobi is safe to do, but cost too much stamina. Deflecting with a PK is not safe and doesn't do a lot of damage. Orochi got two options with deflect:
A) heavy deflect that does a lot of damage, but unsafe (fair enough I guess)
B) light deflect that is safe ( from my little experience with him), but not much damage.
Overall 10/10 you are better off doing a parry than a deflect.