Northrend "Easter" Egg

Personally I think Blizzard wanted us to find this little homage because the Artwork Page led me right to it.

Given the artwork of the Walrus creature and the Moai-like Statues they really led us to this mental image:

Then all it took was one jump to the Wikipedia Page on the Moai Statues to see this resemblance in the shape of the new continent in the Wrath of the Lich King Map to The Island of Rapa Nui, aka "Easter Island."