I’ll add that to my “to-do” list but I’m not making any promises that I’ll actually implement it. I have to think through how the UI would be in terms of the setup.
You should be able to achieve the behavior you want already using CoRE or your own SmartApp because “reachable” is a device state and therefore can be seen by CoRE and other SmartApps. Also, you could just include the switches in all of the same routines, etc that turn on/off the hue lights and just have them programmed based on the expected behavior. If you expect a switch to be off but it’s really on, and you send an on command, it doesn’t hurt anything.
The biggest issue you’re going to run into with having Hue lights set up like this is that there’s no way of knowing how quickly a device will become reachable when power is returned. So if you want to turn on the light and set a color, you need some delay but there’s no way of knowing how long of a delay. You can listen to the “reachable” state, but the delay will be increased due to delays from the cloud, etc.