If you could travel back in time, how would you change Bitcoin?

[tromp]

I'd employ a different proof-of-work that doesn't provide much benefit to GPUs/ASICs,
but rather depends on many gigabytes of memory (just for generating, not for verifying)

Well, that's what I'm trying to design right now:)

-John

Where could we read more about ur design?

I'll announce the design in this forum, hopefully within a week.

-John

Well, it took two days longer, but see the Cuckoo Cycle proof-of-work announcement in the Discussion forum.