Putting aside, momentarily, the process for this change, the change itself, IMHO, makes sense. As a long time Unix/Linux user, yes I am aware that everything in Unix is a file, thats not just a characteristic, its a key feature. But only at a Operating System level. I know for example, you can open a directory with vi, but I have no idea what you happen if I wrote changes to it ....
For an application, a file is different to a directory, an application does not care how a directory is treated by the OS, it cares that a directory can contain files, it cannot 'open' a directory to read data, it cannot find multiple files in a file.
If, at an application level, I want to know if a directory exists, it seems sensible to me to use DirectoryExists(). Similarly, for a file, FileExists(). I care not that its Delphi compatible, its sensible in its own right. At an application level.
Davo