I'd like to view my .md files on mobile fully styled. Most of all I'd like GFM support for tables or at least render tabstopps, so I can see the table in its ASCII art-isch design.
There's currently no way to preview those kind of files from within the Dropbox app and I can certainly pass along your feature request to our development team.
In the meantime, as a workaround, you can use the "open in" feature in iOS and open the files with another app installed in your device that can open those files.