I've read through the primer and it looks good to me, some random comments :

• I had trouble choosing from the list of the weapons, usually a sign of good balance
• I like that even though we have classes everyone kind of works the same way, both from a level of stats + skills to do actions and with the powers activated by blood points, having the same structure for casters and non-casters helps with keeping their potential close.
• Even considering the above i mildly dislike that the specializations are so encompassing for the class, for warriors and experts i would like to see some shared traits and powers for when you don't feel like picking something exotic, like for instance the triple shot ability of the viper seems pretty generic, why wouldn't the ninja be able to do that as well ?
• I like the resource management of wounds and equipment through time coupled with clear ways to handle them
• You have a skill to research through heap of books ;) it's a thing i tend to do often and our gm is always annoyed when the skill is not included