I'd like a weekend even where our characters are level 28/30 [in HM] bosses with double damage, the aura, the lot.
I doubt this will ever be done, but I think it would be cool.
Don't make it an event, just implement it into the game.
Call it "God Mode", and make it purely for fun of those who have Vanquished and Guarded a continent, or for EotN players, anyone who has Legendary Master of the North.