Automatic line breaking
When typing long text in gedit line breaks have to be set manually. Afterwards, when editing the text, this results in long and short lines. The text looks ugly then.
So it would be nice, if gedit makes line breaks automatically after a specified number of columns (only between words, certainly).
However, there has to be a difference between line breaks that have been set manually and those that are introduced automatically. Don't confuse it with the line-warp feature, since these line breaks are not saved, and long lines (even if they are warped), are slowing down gedit quite a lot.
The same feature is implemented in the e-mail editor window of evolution.