He will never appear, because he has million of bitcoins and this mean,
he is or will be one of the richest persons on this planet.
So when he will be seen, then his live will be not more the same,
he would be pursued at every turn he make for the rest of his life.
It's safe to assume that at this point satoshi's coin are lost forever, he doesn't own them. It wouldn't benefit anyone if he went public tho, he would still be threatened even if he legitimately lost control of his coins.