There are somethings I really wanted to see change in SP 2013 that have not changed. Right now my list of major let downs are:
Content Types: How content types are created and managed in SharePoint is highly confusing, and I have found myself wasting dozens of hours trying to sort which the right content type is. 2013 just copies content types over from 2010.
List settings, still its way to easy to delete things by accident, and the list configuration page is still to long and too ugly. Why not a nice WYSIWYG and why can't I modify many lists at the same time? This is still a pretty poor UI for managing a core SharePoint information feature.
Tables, there still a tables all over SharePiont 2013, especially in the calendar view.