Preferences for layers panel
Obviously there are a lot of ideas and requests for the layers panel because everyone wants to customize it for their own uses. Adding a bunch of options in the preferences panel would be better than a lot of "permanent" changes.
I don't like the fact that every element is on a separate layer at all, for my projects it is not necessary. In InDesign I get to choose what elements are on which layer - that would be sooooooo nice in Illustrator