Change difficulty rule: no more exclude members from the PoW process
Today with DUP 0.4, only a 1/3 of the nodes can find the next block. We can see that when there are big forks, some of the branches get stuck, and that might become stuck branches.
As of DUP 0.4, we changed the difficulty rule a bit to introduce a handicap based on personal block issuance.
I suppose we should just generalize this rule, so no fork will be stuck, ever, and anyone can pursue its own fork alone if he wants to, no matter if that takes days, weeks or months to reach a difficulty adapted to its new situation.