There are two new sandboxes in world. They are located to the west of Cordova. Newcomb and Goguen. Newcomb is set 'no scripts' for those who just wish to build.
You may also notice that many of the interior spaces have been filled with water sims. These are not event sims or sandboxes but really just open space to fly or boat across.
I don't have a schedule for when or if other "void" spaces will be filled.
Have fun!