Re: User Interface ....
Let me preface this by stating that I love my Prius. It's a truly amazing car. But... there is always room for improvement, and in case of the Prius I agree that some ergonomic aspects leave something to be desired.
I agree with Taniwha, the dimming trim wheel can be improved. One thing I noted is that the clock LEDs do not dim. At the lowest setting, all is well except the clock is glaring by comparison.
It's a common issue thought, in every car I have ever had, there was always one light source that was left out of the dimming circuit: either the clock, or the AC indicator light, or the radio controls, or.....
Turning off auto climate in any of my cars that had the feature did the same: leave all as is. For example, if you turn auto ac off after it was set to, say 76 degrees F, the compressor is off but the temp is still set to 76, resulting in pumping in hot air.
Engineers: maybe there can be two buttons or two ways to turn off auto ac: one which leaves all as is, the other that sets air flow to minimum, and temp to max cold (so that no heat is mixed into air flow).
Having said all that, I enjoy my Prius, 'Signorina Elettra'