One of the most usable improvements I found is the way how results are displayed/ordered in Find Usages Logical View.
In earlier versions it was quite hard to find what are you looking for. Attempting to get usages of a method having common name such as init(), setHandler() or run() might return hundreds of results. The only way to figure out a location of a file where usage occurred was to place a mouse over a file name and wait for a tooltip to display.
Find Usages - Logical View is way better organized in NetBeans IDE 7.3 Beta 2.
Hopefully this change will find it's way to Refactoring - Logical View in final NetBeans IDE 7.3 release.