The [blog] shortcode has two styles, to get the more compact style you need to use the shortcode in a Text widget added to a sidebar area, and then add that sidebar area to your content using the [sidebar] shortcode.
It works. I just tried it on my Mingle sandbox site. So the problem is not with the theme, the problem is with your content. All I can do is tell you how this is done. I cannot do the work for you and if you cannot implement what I am telling you then there is nothing further I can do other than recommend that you hire a professional developer to help you.