This game is totally interesting right now. I wanted to play the Death Knight to get a feel for it and see which I would prefer. I definitely think it would be awesome to switch over. They are definitely very powerful chars at just level 55. Here are the quests that I completed. I am not going to give too much detail because it’s likely something will change when it is released.
In Service of the Lich King – Redeem through portal at 48, 31 (walks around) Instructor Razuvious
[The Emblazoned Runeblade] 47, 31
[Dominion Over Acherus] 2nd floor (not using the portal) 47, 26
[Company of the Damned] 50, 32
[The Eye Of Acherus]
Back to Lich King through the portal on the 1st floor
[Death Comes From On High] no coords.
[The Might Of The Scourge]
51, 34 through center portal
[The Scarlet Harvest]
[If Chaos Drives, Let Suffering Hold The Reins]
All quests are in the area.
Also, here are some pictures.