For the future SketchUp 2016 version I would like to see some UI changes/improvements. I am personally “done” with floating windows and would prefer SketchUp for Mac more like the Windows version.
Some more topics on my wish-list:
Updated UI no more floating windows in Mac Version
Guides in Layout
Rulers in Layout
Batch Relink for referenced photo-files in Layout
Batch export option for all scenes as .jpg etc.
Option to see materials bigger in colour/material window
Natural scrolling option (Yes, I would prefer it)
Preview option in Finder
As always it is a matter of personal preference. Mine is an interior design / architecture viewing angle. Other professions may feel completely different.