Let's give em a bit of time to explain things because we don't know much at the moment.
While the blue hair? Maybe he just...grows out of it when he gets older. First I thought that it was a different time line where all those years of peace made him weak and unable to transform but he clearly says he is the same one that went back in time to the Android/Cell Saga. So this peace would not have lasted long enough for him to deteriorate so fast. Black Goku looks more like Goten. But he isn't in that timeline.

Guess we'll see next week.