A personal need, for which I didn’t find an immediate response.
So here’s an administrator plugin whose primary purpose is to swap the “Body” and “Excerpt” input fields.
Rejected at the end of the column, the “Body” leaves a place that can be reused. The helpfile explains how.
The plugin uses the pluggable_ui features which launched in Textpattern 4.2.0 Textpattern, therefore it is the minimum required version.
For the rest (download support) is as usual.