It would be nice to use layer command box to Duplicate layer and Duplicate layer with objects.
Also when deleting more than one layer the option to delete all selected, instead of having to cycle through all selected layers. Like WinRhino.
I usually have to do 5-10 different versions for renders, so the duplicate with objects comes in handy so I can keep different versions With their materials.
I also always have a working copy and a copy I send outside work for casting. So they just get basic file. Hence the need to delete lots of layers, sometimes.