The climate thing I miss the most in a Tesla is frickin' VENT mode. In my GFs Maverick back in the '80s the lever just went from Heat to Vent. Personally, I had a VW Bus, so there was no climate control. As cars got AC that vent control lever was still there, along with an AC button that cooled the outside or heated air. If you were going up a hill and you wanted full horsepower you just touched the AC button again and it turned off indicated by a light.
With the Tesla, you have to turn the AC button off, but additionally, you have to turn the temp to the bottom (LO) so the electric heat doesn't come on, and when you do this the fan speed is no longer automatic so you have to manually crank it up if it gets too hot inside or crank it down if it gets too cold outside. Seems like something the car could figure out.
Maybe the heat exchanger is Tesla's way of saying "It's OK to have the climate system on, you are not wasting that much energy", But I just keep shivering in the car that is only warmed by my seat heater, thinking I am being efficient.