I am of course a Newb only having a single programming under my belt of a 3 hour old Flirc but I found something horribly annoying (mostly cause of Harmony) but I can see it could help lots of folks. Giving us the ability while not erasing or learning a command the to playback the mapped IR functions of a remote.
What I mean is:
After I have programmed a map from lets say the "Play" button on my Harmony to the spacebar on a keyboard layout. If I was to press "Play" button on the remote the GUI would identify that the spacebar is the appropriate mapped keystroke by highlighting the spacebar oh, lets say .. red.
I think it would help troubleshooting complex setups.