The issue seems to be the growing rift between players and Horde leadership in Northrend, and the degree to which many of us can't identify with the sub-faction that eventually hijacks the Horde storyline. I burned Saurfang's letter as he asked. I nodded alongside Golluk Rockfist as he told Horde players, "You are leaving to the Ruby Dragonshrine. This is not a request." I sat with Thrall in his darkest moments in the Undercity throne room, when he realized that everything was lost.
By contrast, I /facepalmed my way through Icecrown.
Spoiler material past the break.