What idiot that is capable of stealing 750k of coins is going to risk it even entering an exchange? How many hacks have we seen of X amount of coins enter the free market? None? We will probably never see those coins again since it going to be sold in large chunks to heavy hitters.
That's why coins are stolen: to be never used again...
Do you know the addresses that got double, triple, endless payouts from Gox? If so we can check if the coins are still there.
Why not using mixers, gambling sites and so on to stray the coins and then sell them?