Boards
If CDs came in DVD style boxes
I think I'd still be an avid fan. Larger artwork, they line up nice and neatly with wider spines. You can slip a fatter booklet inside and there is room for 2,3 disks if you wish. They stay in good condition, you can drop them or frisbee them across the room no problems.
Compare this to crystal cases. Over time the little nubbin inside breaks, the outside loses its shine, sliding the inlay results in it getting all fucked by the plastic grips. The hinge can easily break if one of the tiny plastic nobs breaks or wears down. In fact, everything single thing about crystal cases is awful.