If anyone is interested in some things that Alex actually did in WoW:
Classic: The Fordring, Darrowshire, Linkin, The Demon Whose Name We Do Not Speak, and "Of Love and Family" quest lines. Basically every epic questline that you remember fondly in classic.
Wrath: The entire questline that culminated in The Wrathgate. The in-game cinematic where Putricide betrays everyone was his baby; he was really excited in IRC for everyone to get through that quest line and see how it ended.
Cataclysm: "The Day that Deathwing Came" questline in Badlands, most of the Silverpine Forest re-design, Hillsbrad, The Barrens, etc...
If you've paid close attention to quests in WoW, you can tell which ones Alex has written because of the dialogue; he's easily the best character/dialogue writer Blizz has had. Personally, I'm very happy if his creative goals get to span the game.