Yikes, I've always appreciated how I can drag the little document icon where ever I like (like a terminal.app window) to do something else to the file. Also the click and hold key to see the folder hierarchy or open the folder even in the Finder. Those features are positively ancient, they also added the little drop down arrow to the right recently. I hope windows in programs like Preview.app behave at least like how Quicktime Player.app windows behave today, where the title bar with the document icon appear upon the mouse entering the window.
Document based apps have all kept the title and document icon.
With the half-exception of Safari [which had the 'fold heirarchy'], the apps that have lost the standard title bar never had these features, and what has been removed is simply the restating things visible in the menu-bar and source list.
