Oh, I feel for you, radio behavior is such a long standing feature that has been ingrained in minds of more than one generation of drivers. Strange choice from Subaru. I looked it up, it seems that the problem was also present on Outbacks, fixed in update for 2018 model.
As for the freshness of a renter's UX observations, personally, I'd find it less reliable due to different objective vs. a future owner. I would dismiss a lot of seeming inefficiencies of design just due to my unfamiliarity with vendor 'concept' and would kludge it for the short duration of the rental.
On the other hand, if shopping for a new car, test-driving one, my mindset would be a lot more critical.
I remember, at one time having to pull over the highway just to figure out, where was the headlights switch on the fine Dodge Charger. Used to Japanese cars, I would not expect it to be off the steering wheel stalks, but as a knob near the door. Turns out, it's another 'concept'.
Another example is the hand-brake pedal (!). Makes sense in a way. That one entered my memory bank via a nice Toyota Prius, at 4 in the morning, starting my the way to the airport from the darkness of parking lot. Previous share driver left it engaged, manifested itself with a dash warning and very squeeeeky and slow drive.... Luckily, there was a user manual in the car.