If you have Vim optimized for coding, probably you’ll have some problem for writing on it. The first one that comes out for me as soon as I started to writing markdown files in Vim was the word wrap question, any sentence comes longer easily and you can’t read it anymore if you have set Vim to not wrap your code.

If you want to configure your Vim to wrap long lines only in markdown files, all you have to do is to create a ftplugin for markdown files:

" after/ftplugin/markdown.vim
setlocal wrap