But yeah, Claymore does this quite a bit. Theres all this talk about how the Yoki within them will eventually take over them... yet there are all these cases of people like Miria and the people who were up north for 7 years, who never had any problems. I mean, even given that they were suppressing their Yoki... I don't think it would have had such an extreme effect. Surely one of them would have gone mad by now, without being brought back. And the same applies to how those who are "half-awakened" could permanently awaken at any time. It just never happens.
I know Manga plots aren't really supposed to be perfect, but its fun to poke holes!