As a human-con-sword, your parry is already useless (20str 20dex).
Will you get a great boost now? Or you won't?
In other words, will the legacy push you toward giant/staff parry or toward yourself/staff parry?

Editted to add: I think it pushes you toward yourself/staff parry. As I didn't see much better in my felar/staff, which I should have seen if it was going to push me to giant/staff.