On Indigo on the mac I'd love to see a replace device a with device b function. Whenever an Insteon device such as a LampLinc fails (which seems to happen all too often to me) I would be able to plug a new LampLinc in and tell Indigo that this device is replacing the old device without having to manually add the new device to all the action groups etc. that the old device is in and remove the old device too.
On the iOS app
1 - Make the app HomeKit aware so it can control other Homekit devices
2 - Add a home page or summary page or whatever you would call it where I can add action groups or devices that I access frequently
3 - Widgets please! Let me access frequently used actions from the Today pulldown