Empty spots in the last 2 cities

Presumably, these spaces were intended for the artisan that would have been the Mystic, whose function varied over time, but originally included identification, crafting spellcaster items, and creating scrolls and charms. As these things were removed or made simpler, her purpose was obviated and so she was removed. To quote Blizzard on the matter:

The design team is currently looking at systems and cleaning them up, removing any superfluous system objectives and those that are beyond fixing. Thus, we're removing the Mystic artisan. As we look at the big picture, the Mystic simply wasn’t adding anything to our customization system. Enhancement was really just the socket and gem system with a different name, and it would prolong the release of the game even further to go back to the drawing board and differentiate it, so we’ll revisit the Mystic and enhancements at a later time. Removing her from the game took some time, but it’s nowhere near the efforts that would be required to flesh out a better customization system. We hope she’ll be able to join your caravan in the future, but for now we’re going to focus on the extensive customization options the game already offers.