I'm sure some people here already do this but many people overlook this and forget. With the new expansion comes a lot of people who are going to make worgen. (This applies to goblins too but who's going to make those?)
You can create a lvl 1 character and reserve your worgen name ahead of time. When you finally get the expansion you can delete your character and name the worgen with the name you reserved.
Feel free to post clever names for other members to use (if you don't mind your name being used on other servers haha) but if you're lucky you might be able to name one "Worgen" or something.