Coming from a Corolla or older Camry 2.5 might feel like a V6 but it ain't.From the ignition timing/spark advance curve. It feels more advanced on the 2015 4 cyl models which makes them feel lively and punchy as though there was a V6 was under the hood. And also contributes to making the car able to maintain 70-80 mph speeds on the highway with only very slight pressure on the accelerator pedal.
The 6-speed transmission on the 2015 4 cyl models is programmed to keep the car in the lower gears for longer periods of time when the driver is accelerating or going up hills including slight inclines. So the car never feels bogged down in too high of a gear.
The combination of aggressive spark timing and lower gear transmission programming really makes the 2015 4 cyl models feel athletic plus contributes to outstanding fuel economy at steady highway speeds (e.g. up to 500 miles on a tank of gas).
All specs are identical, no one but you saying anything about new soft, the 2015 is a bit heavier, but peppier, more responsive and more economical according to some.
At steady HWY speeds "older" 2012-14 can do up to 600-650 miles, so 500 is not that impressive.
No offense, but your sense of refinement, better acceleration and fuel economy are symptoms of a new car fever/smell/euphoria and there is no other explanation to that.
You bought a good nice new car, but there is no reason to to over-exaggerate and over state anything about it.
Enjoy your new car.