Well, Kaigan is not bloodline ability but a technique/skill which is forbidden. If take example Karin had unique sort chakra sensing ability (or rather monstrously increased profiency in given skill which can be borderline of new bloodline or simply very advanced technique). Her truly bloodline or her family ability was probably the ability heal people who bit on her body (similar fashion like her mother had it and died using that ability as she was forced overusing it), while her chakra sensing came later in life.<br/><br/>I agree it's sort of dumb power boost but how you would mechanically work with ability which literally allows you 'see few seconds in future'? Such insight in itself is broken; if we would go anime standards, a guy who can perfectly predict few seconds in future cannot be hit, knows always what your going to do in fight and counter it perfectly and is able land perfect hits all the time. So a flat +6 insight bonus to all attack rolls, defense and damage with physical melee/ranged attacks is rather tame compared how broken conceptually given ability is.<br/><br/>But indeed I intended Jin-Ryu being regular guy so I can drop the Eyes of Divination and only special being his low-light vision and weird colored eyes (which had earned his nickname anyways). Albeit it's true Jin is clearly chinese word, but Naruto is filled with weird naming conventions so name could work without problems :P.