Well obviously, as the cinematic is from Blizzard, the CGI was top-notch. Many are turned away by this trailer for its failure to showcase the upcoming Death Knight class in action, or really showcasing any true class at all. To be honest, I believe that the trailer was so well-done that there was no need to actually show anything off. This trailer is the definition of a Warcraft event, as not only does it elaborate and emphasize the immense severity and evil of Arthas's betrayal through King Terenas's monologue, but through the artists' work at Blizzard, they are actually able to set huge meaning for an upcoming landmark in one area of the expansion. It showcased exactly what the expansion is about, the wrath that Arthas intends to spread throughout Azeroth, and why the Alliance and Horde must stop him before he's able to complete his task.
A true trailer for the long-time Warcraft fans, I loved it. While it may not appeal to those who failed to play previous Warcraft games as strongly, perhaps it will inspire them to go and look into the lore further.