Keccak is SHA3..
which will totally kill off ASICs of todays current design.. and would cause the system to take weeks to solve one block because the difficulty is soo high, by the time that 2016 blocks are solved (years) to then downgrade difficulty, would be too late...
Yes, it will kill off today's ASICS. But I disagree about the difficulty. Obviously the hardfork would not only change the PoW but initialize the difficulty to a reasonable value for that PoW.