Not saying the Castle Cake was a good idea or attractive, but you have to admire how much they embraced the concept and transformed the castle (the front of it anyway). Even looking at this picture I can't help but smile; it's oddly endearing in that "They really did it!" sort of way. As @MisterPenguin said above, certainly no chance we'd see anything as ambitious now because it would screw up the projection mapping.
And at least it was actually temporary, unlike certain other "temporary" icon embellishments that long overstayed their welcomes.