Take any scenario where rsync is useful: backups, updating remote / hosted content, etc. KDE is capable of managing all sorts of connections in a graphical environment, rather than console (or dedicated clients for each protocol). There should, then, be a graphical alternative to the rsync command.

Reproducible: Always

Steps to Reproduce:
Select a folder from one [window / tab / panel], and drop it into another panel. This can be a different directory, a USB drive, a remote machine on SMB or FTP, whatever, thanks to KIO magic. The little menu appears with "Move here", "Copy here", "Link here". There should be an option: "Synchronise here"!


Expected Results:  
I would expect this to work as either "rsync -a" or "rsync -a --del", which together cover the majority of usage scenarios. If files are found in the destination that are missing from source (which is when the --del option becomes interesting), a confirmation dialogue should appear, "Delete files in destination folder that are absent in content being dropped?" (similar to overwrite dialogue on copying) -- the behaviour after "yes" corresponds to "rsync -a --del", behaviour after "no" corresponds to "rsync -a".

While this will never cover the full versatility of rsync, I think this would provide a very powerful tool for everyday file management -- synchronising between hard discs, cloud, usb discs, backup devices.