I would like to see a general/customisable error for the set heating commands. there's just the one possibility at the moment of "unwilling to set value" because "thermostat is off". what about if the temperature is out of range or if the thermostat is on already when we ask to turn it on? why not provide a "customValueNotSet" where Alexa says whatever we return in the payload "description"?
also, we seem to be missing a query for smart home devices and heating in particular, so we can ask "what's the heating doing?"