I recently had to fix 50 files of plain text user content to be more readable. Line breaks needed to be added to make the paragraphs look more coherent. Here is my solution to fixing a file quickly.
Add the following to your .vimrc Set 100 to the max number of characters that you want in a line.
:nmap <c-a> ggVGgq
:setlocal textwidth=100
save and quit.
Open up a file to edit, press Control-A and voila!
