Your understanding of decentralization is heavily flawed. There are less than 10 mining pools that run full nodes and the miners don't even have to process the blockchain. Proof of Work became Delegated Proof of Work.
DPOS is the most decentralized in terms of UNIQUE BLOCK PRODUCERS PER CONFIRMATION WINDOW. It is also the only chain that has incentives aligned properly.
RE: EOS.IO software will not suffer from Denial of Service (DOS) attacks like Ethereum