At first this note looks like any of the other intel that you've been looking for. However, a quick perusal of its contents disabuses you of this notion.
The letter conveys that Grand Admiral Westwind is present somewhere on the island, but that he is keeping himself secluded for now. He speaks of a glorious day that is coming soon in which the Scarlet Onslaught will wash over first the Lich King and then the rest of world to finally bring order to Azeroth.
The lord-commander will want to see this!
Scarlet Onslaught intel is to be delivered to Aurochs Grimbane.
<The lord-commander gives you an expectant look by way of a dismissal.>
A note written by Westwind? Why didn't you say so?
<Arete tears the letter from your hand to read it.>
The fool! He's actually here?!
<The lord-commander laughs.>
This is new information. I wonder how he imagines that he's going to conquer the world once he's taken down the Lich King? Not that he could accomplish either task in his wildest imaginings.