Kaneki is not "back". Now he's switched from imitating Arima to Hide and even pushed in some Urie type dialogue, which wasn't translated. Lots of people think that the his true self translates to Anteiku Kaneki, even though that's not true, as Hide himself said Kaneki was always wearing a mask during that time, which was again confirmed in chapter 53.
It'd be a treat if we could see the real Ken before he dies.
Then there would be no need for Tsuneyoshi to request raising a soldier stronger than Arima, since they could just artificially make another one like him.