- removing clutter (zapping toolbars, splash screens and the ilk)
- making very small tweaks to keyboard bindings so that it works more like Epsilon
I don't think that any of the Emacs improvements made over the last decade or more have done anything to my quality of life in Emacs. Rather, each release is more "what do I have to turn off this time?"
Fortunately, getting to bare-bones Emacs is not hard; with commercial editors it's often much harder to undo the damage of gratuitous "marketing checkbox" features. [I'm looking at you, Visual Studio 2013...]