15 years have passed and we still don't know who he is, is there still a hype about him or anyone really cares or expect that he will appear one day? I don't think so.
Hype? We can see how much hype there is for him and his identity. Movies and documentaries are being created in his name, what else would you call hype? The world might not expect him to appear, but they surely care about this thing in particular even if they don't care about him and his safety.
At this point, I think that he is most likely dead and for that reason, he will never appear.
Even if we imagine that he is alive, is there any benefit for him to appear? If he appears, the whole world will talk about him for a long time, governments will fill lawsuits or will request his extradition in the worst case but in the best case, he will have to hire bodyguards and won't be able to freely walk in the street and should always be in fear of something bad.
He wouldn't hide his identity in the first place if he had the wish to come out to the public eventually. He knew what he is doing, and he did it probably because he anticipated the future and the consequences of him having his identity publicly revealed.
By the way, this anonymity is an asset, it makes Bitcoin even more decentralized because we don't know the owner, he doesn't appear, so at the moment, there doesn't exist any central power.
Not necessarily. His revealing his identity wouldn't have any difference in the decentralization of Bitcoin but it will surely be life-threatening for himself. So he shouldn't and wouldn't do it at all.