1. Even if Satoshi becomes known, it won't turn Bitcoin into a centralized system.
The only thing that he may influence for sometime is price.
Bitcoin is decentralized because it was built that way not because Satoshi is anonymous.
Bitcoin has no head just a creator.
Whether directly or indirectly, Satoshi’s stance on bitcoin and his disappearance really have great impact to what bitcoin is today. We need to know that bitcoin is anonymously and decentralized but that may not have been fully achievable by now if Satoshi is known because government will be on his trail. In one way or the other, they may have forced him to make some changes to the system which will definitely affect the overall working conditions of bitcoin.
When the creator of bitcoin is forced, he may compromised and leak out some confidentiality that are good for the development of bitcoin. If bitcoin would have succeeded this far without him going into hiding, then by now i feel he should be known. He knows best why he went into hiding and I respect his opinion as it has brought development to Bitcoin and have made it come this far in the global financial market.