The DAO hack was a smart contract breach of the DAO only. It had nothing to do with the Ethereum core protocol. IOTA concerns many cryptographic experts b/c its not full consensus many times over like blockchain + Raiden or LN will allow very cheap transactions in the future. EOS and Steem are also "free" transactions. Apps will be built for IOT plugin to use with ETH, NEO, EOS and other Blockchain based systems. The problem with IOTA is its not secure and there is little advantage over off chain scaling. Any blockchain can do IOT in the future not just IOTA like its branded.
RE: IOTA is problematic ($MIOTA) Broken Internet of Things