The dragons and the White Walkers have tread similar paths. They've both been teased since the very beginning of the show, they're both incredibly powerful and we're only now beginning to see what they can do, yet we don't know their potential, their end goal, or their impact on the final story. The White Walker scenes are also growing with each passing season to the point where only a wall-shattering performance can top the sheer carnage that went down at Hardhome. I honestly believe Thrones is going to pull off something completely insane for the White Walkers' 'moment' this season, and the pressure falls squarely on Benioff and Weiss to 100% nail it.