I'd also like over-the-air programming. We've already needed customers to ship back our device twice because it needed to be reprogrammed. If our app could do the re-programming it would make so much more sense. To add to the list of reprogrammable BLE devices: FlowerPower and SensorTag
For security it would be best if the developer could add a private key stored in the rfduino flash and this key is used to verify a signature on the incoming code. Since the sketch can already write to Flash, I suspect I could hack this in now. A 'bootloading' sketch would start up and then jump to a program stored in flash. The bootloading sketch would support updating this program over the air. I don't have time to do that though, but perhaps someone else does.