You can always tell who never played W3, or Horde. I vaguely knew who she was, in Vanilla, from W3. Most of the people that I played with in my guild were new to WoW, or from Everquest, so they didn't understand her character either.
Now fire back that of course you played W3, even though anyone who did would never post what you did. I'm not a Sylvanas fanboy, but I understood her character from the beginning in WoW, and thought she had the most tragic story arc Metzen made, even though she didn't get used in a visible way for the Alliance until Wrath. The same could be said for Jaina, she stood in a tower in Theramore for all of vanilla, and was just a non-loot piñata for the Horde to have fun trying to kill.