Can i take the powerful strikes blade skill more then one? It doesn't say anything about not being able to but it also doesn't say that i will be able to take it more then once.
"The soulknife’s psychic strike deals an additional 1d8 damage."
Any time you see a fraction for a favor class bonus, that means that you have to select that favor class bonus X amount of times before getting the bonus.
So in your case then yes, you have to select the bonus twice to get the extra damage.
I'm trying to figure out how the half-orc soulknife favored class would work. It says to add +1/2 to the soulknife's psychic strike damage, so does that mean every two levels i would add +1 damage to my psychic strike damage?