I have imported I don't know how many text documents into Word just to manipulate them with find and replace. It works, it's simple, and it's repeatable. It's quite easy to replace anything, including replacing a character with the same character of a different size, bold/italic/underline attribute and/or font. Really.
Of course most of what I did was to eliminate excess crap from text dumps (or even multiple levels of ">" in emails that included who knows how many forwards), so I usually saved the results as text instead of .doc files, but you can do whatever you want with the results.