The only tool in the world that can preserve docx structure in txt format.
To translate a word document (.docx) to a text document (.txt) use the following command:
DocxToTxt.exe MyDocument.docx MyText.txt
To add borders to tables use the -e parameter like so:
DocxToTxt.exe MyDocument.docx MyText.txt -e
You can compile the code from source using Visual Studio.