The following improvements are available in nano version 2.6:
Trailing whitespace can be snipped from justified paragraphs.
Better feedback when a file is unwritable or a directory inaccessible.
Bindable functions for deleting a word to the left and to the right.
A bindable function for saving the current file without prompting for its name.
Commenting/uncommenting lines with a single keystroke (M-3).
Resizing the window does not exit from help viewer nor file browser.
On some terminals Ctrl+Left and Ctrl+Right jump to previous and next word.
A steadier movement of the highlight in the file browser.