When Visio 2013 first came out in early 2013 we noticed a bug where inserted AutoCAD files did not display at the full resolution and looked blurry at high zoom levels.  We documented the issue in the D-Tools support wiki and I notified my contacts within the Visio division at Microsoft.  After a couple of emails Microsoft said that they would fix this issue in the Visio 2013 Service Pack 1, due in March 2013.

I am pleased to announce that this fix has been implemented by Microsoft and SP1 is available for download at the following link.  http://support.microsoft.com/kb/2817443

I was going to do a full review on this topic but VisGuy Chris Roth beat me to it.  This article tells you everything you need to know about this specific problem and solution.  http://www.visguy.com/2014/02/28/visio-2013-cad-import-fixed-with-sp1/

Here is a CAD file in Visio before SP1

Same file after SP1

Problem solved.  Thank you Visio division of Microsoft for getting this taken care of.  It means a lot to all of the users that rely on AutoCAD compatibility to do their jobs.