Going from Outlook 20xx to 2013, you really lose a lot of emails in the message view with the large font format and view settings.
You can get very close to 2010 following these settings: http://www.msoutlook.info/question/755
Here’s the gist, but hit the link for screen shots and details:
Decrease the name of the sender back to a similar size as in Outlook 2010
Go to “Conditional Formatting”
To reduce the display size of the sender name, add the following very simple Conditional Formatting rule by pressing the “Add” button:
Name: Smaller
Font: Smaller
Condition: No need to set any
Remove the first line of the message:
To remove the first line of the message from the Message List, switch to the View tab, click on the Message Preview menu button and select: Off