What's up with it?
I think it's long overdue that Double-Up's recast be lowered. 8 seconds is just ridiculous. Even after watching the animation to see what number we rolled, it's still about another 4-6 seconds of waiting before we can Double-Up again.
With the recent adjustment to rolling an 11, it's possible for a Corsair to keep up many more buffs on more people, and to keep lucky numbers/11s up constantly... but it's tough when we're spending most of our buffing time waiting for Double-Up.