- Show subdirectories with one simple click: When a remote folder is clicked (1 simple click) in a folder of the directory tree panel, then the subdirectories are shown, and a "+" is added to the folder (if some subdirectory exists). It's a very useful feature of winscp. Filezilla doesn't have this feature (filezilla requires double click, instead of simple click, to show subdirectories).
- Use a different folder icon for non-explored directories: When a remote directory hasn't been still explored (=clicked), it's shown with a "?" on the folder icon in the directory tree panel. Once a directory has been explored, the "?" is removed from the icon forever (well, for the rest of the session). It's a very useful feature of filezilla. Winscp doesn't have this feature. As a consecuence, in winscp's remote tree panel, there is no visual difference between a non-explored folder and a explored folder with no subdirectories (both of them have the same icon; none of the have a "+" at the left).
So my suggestion is to add (at remote directory tree panel) a "?" symbol (or a different color, or a different icon) to the folder icons that are still not explored. This will give visual&quick information to the user about directories that don't have any subdirectories, and about directories that could have subdirectories.