Hovering tooltip image preview (for desktop/mouse usage in listview)
I'd like to bring back an old idea for consideration, which would allow me to avoid using the icon view (or zoomed-in listview) entirely, and make me more efficient by occasionally letting me compare some images I care about before opening them: showing a quick tooltip containing a medium-sized thumbnail of images and documents (when the thumbnails are available/cached) when hovering with the mouse. This would allow me to keep the beautiful efficiency of a clean "generic icons" list in listview, remove the need for Sushi (Sushi is buggy, slow, it always felt "tacked on", and requires me to select a file and use the spacebar key... and seriously, who uses Sushi to play videos? ;)
This is a mockup I had made ten (!!) years ago:
Disregard the fact that the mockup is on top of a desktop and that it has fancy colors and such—remember, it was made ten years ago! Today I would only suggest it as an asynchronous standard GtkTooltip (with gtk_tooltip_set_custom) over Nautilus' listview (I think this would be pointless in iconview mode).
This idea is just meant for high-information-density desktop scenarios where you can use a mouse, it's not meant for touch/mobile (and touch/mobile would probably be using the icon view to display thumbnails).
Just my 2¢ feature suggestion ;)