In JUnit launch configurations, you can now edit the test method:
When the test method is empty, all tests in the class will be run.The particular thing about this feature is that it was already possible to have a single method under test, but it was only available in an arcane way, through a launch shortcut. Select an individual method in the Eclipse editor (I imagine it's also possibly available through an outline or other such adapted view), right-click and select Run As > JUnit Test.
My hope isn't that a small feature like this makes Eclipse more powerful, but that it makes you more powerful. Give it a try and provide feedback on the bug report.
Powerful features lose their worth if people don't know about them, and people won't find out about powerful features if they're hard to find. Word-of-mouth only goes so far.
Whether or not you believe Eclipse users suffer death from a thousand paper cuts (I do like that matrix), every tool has its rough edges. What small usability feature do you think would make a difference?