Whew -- had WN and ATA allowed use of the companion pass on Hawaiian flights, I most certainly would have been impacted by this (the fact that you couldn't use the CP made award travel to Hawaii on WN less attractive to me).
I thought there were some rumors that WN might "pick up" these flights from ATA, but that always seemed doubtful. Please correct me if I'm wrong, but I don't think WN has any ETOPs-qualified aircraft. And the high price of fuel makes long-haul leisure markets less attractive.
It will be interesting to see if US adds any service as a result of this development. I had heard their new Hawaiian routes from PHX were profitable, but I don't know if that's still true with $100 oil.