Takes many bit flips to go from one pattern to another.

If that is the only constraint, wouldn't the goal be to be as far as possible from the only success state?

the distance between success and failure is 28

Maybe, but in practice malware that makes sudo always fail is also bad. At the same time, getting 28 precise distance from row hammer is basically impossible.

i think their bitfields seem specifically chosen to mitigate rowhammer attacks (no repeating elements)?