I control the private keys of my blockchain.info hot wallet and i don't have a big part of my bitcoins in this wallet. But i am not sure it is the case of 1.5 million users. I am sure a lot of them are not able to get their bitcoins if the site is down.
Exactly - and even if they did obtain their private keys, how many would find it straightforward to use bitcoin-qt.exe command line API or run the gauntlet with some other wallet app.