As a Toyota hybrid owner, you see that Toyota's design is kinda at a local optimum, hitting limits in every direction which sometimes rear their head in the user experience.

For example, the sluggish 0-60 is due to the design being unable to get all the power from the engine to the wheels at slow speeds, due to the electrical path through the CVT gearbox being too small.

The funny noises when going down really big hills are due to the system having no way to dump excess energy after the battery is fully charged and being forced to rev the engine at 5000 rpm with no fuel to waste some.

The slow throttle response is due to the engine always running at 80% throttle for efficiency, which means if you suddenly need more power you can only quickly get an additional 20% before waiting for the rpm to slowly rise and give lots of power in a few seconds.

EV's do have similar design limitations (drive on a racetrack and you'll need to let the hardware cool between laps), but they seem easier to overcome by simply sizing the system slightly bigger to hide the limits.

You make valid points, but to get almost 40 mpg in something that would get closer to 20 mpg without the hybrid system, there are gonna be some drawbacks.