It looks like we recently implemented a hotfix that deals with Nat Pagle and the quests associated with him (i.e. "The Great Angler Returns"). He may have temporarily despawned when the fix went in and will return shortly but we're looking into it.
It looks like Nat went on walkabout. We're looking into his absence but I'm afraid I do not have any additional information at the moment.
We hope to have him back in place as soon as we can, a little worse for wear but otherwise intact.
Alright, we have a bit more information and have an indication of what may be causing an issue for some of you.
It seems there was a recent change to the system that prevents characters with Heirlooms in their inventory from transferring. This is an intentional change.
The error message that was intended to go in didn't make it with this push. We are working to hotfix the error message to clearly state what is preventing the transfer as soon as we can.
In order to transfer your character you'll need to delete any existing Heirlooms from your character's inventory. You can mail them through the normal Battle.net mail system if you wish, but you will be unable to transfer with the physical items. Sorry for the confusion, folks.