Remove Shortcode […] from Blog Preview

You can do with PHP. Just remove part where is get_content() and add this:

<?php 
            $content=get_the_content();
            $content = preg_replace('#\[[^\]]+\]#', '',$content);
            echo apply_filters('the_content', $content);
        ?>

That is regular expression added inside content. This regex will remove all tags inside content.