It really doesn't matter, you don't want to know who Satoshi is, then Bitcoin would be tied to a real person, a real person with a history, with faults with perceived conflicts of interest or corruption. We don't want this, it's better to just let the man vanish by his own accord. He didn't want to be a celebrity and it helped the coin.
Although Satoshi is who made this coin that bring positive impact for people but his presence will have no significant impact on the sustainability. What bitcoin needs is world acceptance, which will allow all bitcoin users to use their bitcoin in real shop/offline shop. And if he appeared then probably it will be dangerous for him because he will be target of many people including the government and even criminal groups who want to take advantage of him. Since he is the creator of bitcoin then he should have a lot of bitcoin.