[Scribus] Text Editors

[Roger]

I thought this for a long time, but then I realized I do extensive
> tweaking of kerning and other fine-grained text settings, which could
> not be meaningfully saved back to a plain-text file.

But isn't this what Scribus is about, they wouldn't need to be within a plain
text file.
A text editor, to me is  for very basic layout, spell check and other raw text
operations, not particularly to refine positioning of text items within a frame,
Scribus has tools for that purpose.
Scribus on the other hand is the design and layout tool for placing boxes on a
page be they image or text boxes and providing the ability to manipulate the
contents and positioning.
Roger