How awesome would it be if someone wrote a cornerfix app for the sony nex 5R/6...
failing that, I would settle for something that records the focal length and aperture for manual focus lenses. This way, I don't need to remember what lens I used for each picture.
This type of stuff would be great, we could also add geotagging by way of cell phone GPS while we're at it... probably lots of other great ideas too; as far as I'm aware though, Sony has not made their app framework open architecture.