The Horde portion of the scenario even has a small moral choice. Sylvanas uses the Blight, and the Horde players can either attack the Alliance with a blight-sprayer, or just rescue their own soldiers. Despite a lot of the forum anguish, the vast majority of people in my raid gleefully blighted the Alliance. Though one person said he regretted it afterwards.
The Alliance gets to battle Saurfang, and then Anduin echos Arthas in Warcraft III with his entrance into the throne.
Horde-side, the conversation (not in the video) between Sylvanas and Saurfang was spicy. It drew gasps in raid chat.
Ah, there's the Sylvanas we know and love. Arrogant and snarky. I bet these videos greatly restored her status among Horde players.
For the most part, these scenarios are excellent. Putting major content into the game instead of novels or other secondary media. Blizzard also interleaved game-play and cut-scenes very well.
About the only criticism I have is that the Alliance seems curiously unprepared for the Blight. Here's how I imagine the planning session went down:
King Anduin Wrynn: Our siege towers and armies are ready. Let us march on Lordaeron! Any final concerns?
Sky Admiral Rogers: Sir, what about the Blight? Do we have a plan to deal with it?
Anduin: I don't think Sylvanas will use the Blight.
Rogers: The Forsaken used the Blight at the Wrathgate. They used it at Gilneas and Southshore. Why would the Forsaken avoid using the Blight now?
Anduin: You know, Sky Admiral, I don't think we will need a flying ship in this battle. I'm leaving you behind to guard Stormwind.And that's why our beloved Sky Admiral Rogers wasn't at the Siege of Lordaeron.