There's not much I'm "dying" for in Cinnamon; it's very complete.
I wouldn't mind if the Nemo Actions system got a GUI editor. I think it's such a little known feature...if you go to ~/local/share/nemo/actions, you can add config files that can add items to the right click context menu, including but not limited to shell scripts. I have a few basic ImageMagick scripts that allow me to do things like edit images or convert them from one file format to another just by right clicking a file.
Let's hope they can pull it off soon, XFCE really surprised me with the speed at which they transition but it's a huge project for any DE and we are slowly getting to a point where it's actually neccecary!