I don’t know whether this has been discussed or not, although I suspect others have wished for the same thing, namely:
Integrating the Inspector window in the main window.
I’d add that I’d like to see the Inspector show the path of the document. Often enough, the ‘Container’ name doesn’t tell me quite where the item is. Of course I can choose ‘Reveal in Container’ but then I’ve lost my place in the Record viewer. And besides, it’d be nice to see this info more quickly.