It'd be nice if instead of the Front and Back layer, there's a Z Position Value you can edit for each object. The front and back layer feel too restrictive to make a nice 3D Picture. An editable value like that would provide more variety, especially for games with more complex backgrounds.
Slopes (wedges) would also be very nice to have. Top-down games that display walls at an angle (Metal Gear, Sweet Home) can definitely use this.