So... Beasts are Ninjas but without ranged attacked. I do see your point. A “melee” MM would probably love the set. I am testing a Beast/Kin at the moment. Should not be too hard for them to enjoy all the benefits from Kin but without any defence/resist or -to-hit / -dam protection around them, I could see it may be a problem at a high level.
How about /Dark or /Time. Would that mitigate the problem some what?