Hi! I personally would mood +HP/Nin and -Res/Def. It would really depend on your playstyle and what team you are using it for, but if you want to have a basis, my GNW Sai is mooded for +Nin (because most of his attacks are Ninjutsu based) and -Def (because I value Resistance more in my team). Hope that helps!!

You are absolutely right! It really depends on how people use them, I personally like its passive which replaces the standard attack for a Ninjutsu based attack when there are two or more nin dogs on the field!! Different playstyles for sure!