As we know, the only returning playable class is the Barbarian. However, Jay Wilson recently suggested some classes could return in the Diablo 3 expansion pack.
Source: battle.netBashiok: It is Skovos, and I think this piece was something that Leonard showed and discussed at the WWI Lore and Environment Art panel.
It isn't a location that you'll visit in Diablo III, but the artwork is a good example of the work and thought going in to fleshing out the world of Sanctuary. It's already a very complex world with a lot of locations and events, but a lot of it still isn't visually or contextually realized. As we want to create the feeling of a world outside of your immediate view it's important to create or expand upon the locations and stories of that world.
As we're working to create Diablo III we're also working to create a more visually complete Sanctuary