I'm not trying to render your character completely pointless I'm arguing for the sake that some skills are tied directly into the servant's character. Earned experience, or strength of character. I pointed out mind's eye because its years of training directly channeled into seeing opening, and taking control of the situation through comprehending the technique. Bravery is a skill that is directly that of a person's character. By stealing, or taking away either of those two skills for example is to take a servant's actual years of training, or strength of their will. It works by conceptually taking away something. But I don't believe it should be possible for an opponent to actually take that away from a servant. Sealing, or disrupting it is one thing but to physically take something like that away is something else. 

I'm not arguing its unfair to steal away things like say Knights Tactics by mentally stunting the opposing servant and forcing him to fight plainly. Or even Mana Burst by somehow blocking proper mana channeling. But I'm talking about skills like the aforementioned that are directly tied to someone's personality, or being.

I'm not trying to be unfair, or give you a raw deal I just don't think a phantasm of that would be capable of existing. The previous weapon stealing one certainly does with Benkei but it brings along the deal of rending servants weaponless and many servants do depend on a weapon at this roleplay's intended level; or like Caligula a mass disruption by pure madness enhancement but to actually temporarily steal a servants skill so that it doesn't even belong to them in the first place. Its like taking Shiki's eyes powers away something she was a born with suddenly she doesn't have not because it was disrupted but because suddenly she doesn't have it in the first place. If you find this unacceptable you're free to do as you please in the matter including arguing back in favor, or bowing out.