the flaw of Bitcoin design is not the GPUs, it is the mining pools. They completely invalidate the initial assumption thatr every Bitcoin participator is contributing to the network security. With the pools, only pool owners do. Currently the end miners don't need a Bitcoin client and can't even know for sure which network they are mining for...
I guess you need to use bold and all caps to be heard around here. So, for the third time,
POOLS ARE ONLY A SECURITY THREAT DUE TO AN IMPLEMENTATION DETAIL THAT CAN BE EASILY FIXED. IT IS NOT A FUNDAMENTAL PROBLEM WITH THE DESIGN.