Some usage scenarios:
I want to control fan speeds on the difference between ambient temperature and component temperature. I need to designate one temperature sensor as ambient and have its reading subtracted from the other sensors before those are used to control the fan speed curve. This would stop the fans racing pointlessly on a hot day when the component is already only a little above ambient.
I want to control a fan or a pump on the highest of a number of temperature sensors. For example, with a single water loop running through GPU and CPU blocks, the pump should be controlled by whichever is hotter.
For display simplification purposes, I want to be able to combine several temperature sensors to drive a single graph. For example I have four RAM modules which I would like to combine into 'RAM Temperature'. In some cases the mean value would be appropriate, in some the highest value.
To reduce audible ramping up and down of fans, there should be a variable damping time that applies to slowing the fan down (i.e. it would ramp up immediately as the temperature increases, but would only ramp down slowly as the temperature decreases).
The above and more could be abstracted into the concept of 'virtual sensors'. These would be user-defined sensors which would be a specified mathematical function of one or more physical sensors. Once defined by the user these could be used wherever a physical sensor would be used at present (fan or pump control, graph on the Dashboard etc.