This is a bad design. A person should not get over half through the game only to realize all those points in a dedicated weapon type become useless. If skill books were not such a pain in the rear i could chalk it up as a money sink, but that is simply not the case. with the randomness of acquiring skill books its just bad design for this to happen.
tenebrium skill should probably just be removed and replaced by normal weapon skill.
i would suggest things like letting the stack for reduced amounts or something, but with skill points being limited this would also be a bad design. you simply do not have the points to double-up on a weapon skill like that.
