So I was a Mac user about 10 years ago (don't judge me). I don't miss OS X in general but I was a fan of the Finder's multi column view - where you could see the contents of the selected folder and each parent folder as well (hard to explain but I'm sure you know what i mean). Is there any chance you would consider adding this to Directory Opus? it's particularly good for moving or copying files quickly.
Second request - I used to use a file manager in my mac days called Path Finder. It had a feature called the shelf which was an icon on the left above the favourites. You could drag as many files from as many locations as you wanted to the shelf, then go to a new folder and paste them all there in one go. Really handy!