Speaking of sensors…it would also be nice (for me at least) to monitor the temperature of various places in my house. Example…I would like a remote thermal sensor in my main refrigerator, garage refrigerator, basement mini fridge, and garage deep freezer. This would alert me in case of power outage, or temperature change (freezer getting too warm, etc. Some would say that this may not be related to HVAC thermostat, but I would argue that it is a better picture of all thermal monitoring of my home. The thermostat could be the aggregation point of all things thermal.
[Mod Note: comment relocated to more closely related wishlist topic.]