I was long skeptical of the PC/iDrive/etc. Last year I got a great deal on a used PC and jumped on it, figuring that if I didn't like it, I could easily sell it and get my money back. I ended up keeping it.
The PC does improve throttle response in a different way than just telling the car you are stepping on the pedal harder than you actually are. My theory is that when you step on the pedal, the PC momentarily sends a "pedal to the floor" signal to the car (this lets the car know you are in a hurry so it responds quicker) and then immediately backs it off to however much you are actually pressing the pedal + the boost from whichever mode you are using (city, sport, etc).
For example: If I am on City mode and taking off from a stop by pressing on the gas pedal 20%, the PC might send a 100% pedal spike to the ECU, immediately followed by 30%. If I am on Sport mode, it'd send 100% immediately followed by 40%. Economy mode might be 100% followed by 10% or something.
Again, just a theory based on what I've noticed with it. Whenever I feel like my pedal is laggy, I temporarily turn off the PC and can quickly notice the difference.
There is no magic solution that will make the Camry drive and shift like a sports car, but there are small improvements you can make that can add up. Doing a big-3 electrical upgrade helped with throttle response. Driving around in S8 instead of D is another "trick" that can make the car a bit more responsive and sportier to drive by holding gears a little longer than in drive.