I love the glass walls. They were right on schedule for me too as my current Sim is a Freegan and I'm trying to build and furnish her home by only using her found/crafted items and buying only what I absolutely have to buy...like walls and floors lol. The glass walls mean she didn't have to buy any windows and her home has a cool look, despite her being so tight with money. They also go great with platforms. Make a glass walled room and lift up the floor with the platform arrows and you can make windowsills or display cases. They also make cool balcony fencing on half walls and even shower screens.
Spiral staircases have been long requested here and I'd love to see them too, but we have been assured that the request has been taken to the devs by a CM when we raised it on the previous official forum AHQ.