Yikes, we can shorten that a bit. :-)

    function vimify() {
      (vim - -esbnN -c $@ -c 'w!/dev/fd/3|q!' >/dev/null) 3>&1
    }

    $ echo '<h1>Change Me</h1>' | vimify 'norm vitxiOK I Will'

(Don't forget '-c' if you have more than one transform.)