Blizzard have given us an update on the Korrak’s Revenge fix that will re-enable the event, stating it will be coming later this week.
Korrak’s Revenge (Source)
Today, we determined that the solution for Korrak’s Revenge is going to require both a client fix and a server fix. We’ve got the server side worked out, but the overall restoration of Korrak’s Revenge will require a small client patch. Our plan is to get that out later this week.
We apologize for the delay.