Especially considering that the Unity 8 Ubuntu DE has been scrapped and that Ubuntu will now be using GNOME, I think that it would be really good for GNOME to have some sort of a 3D app-switcher like the one that was in Unity 8. A preview of the Unity 8 one was provided here http://www.omgubuntu.co.uk/wp-content/uploads/2015/06/unity-8-3d-window-switching-750x405.jpg which I think is really quite nice and something that GNOME should actually have, it doesn't obviously have to be exactly the same as the one for Unity 8 was going to be, however our current app-switcher via 'ALT+TAB' is really very basic and it would be nice to give it some more stylish love to go with the rest of this great DE.

I originally filled a report on this downstream a while back, but I've just been asked to file it upstream here. Here is the downstream report: https://bugs.launchpad.net/ubuntu-gnome/+bug/1540104