Ответ Wilke: Well we are already at 5 rounds only. Running too few rounds opens some tmto backdoors I do not like. Replacing blake2b by siphash indeed was an option I thought about before I had the idea that gave way to the current algorithm
Вот эта idea that gave way, которая линейно преобразует списки перед equihash, довольно невнятно описана в том репорте что вы показали