Thinking I may add this to all my posts: I am new to Hyundai vehicles, but what I have seen in other vehicles is.....
Many vehicles are drive by wire. By that, the throttle is controlled by electrical wiring that will open and close the throttle, as opposed to the cable pulled ones of days gone by. With this, the computer is in control. With that, many computers are programed with torque management. This will let the computer limit the intial and overall force you place on the car. From the car companies standpoint, you can see why. The warranty, at minimum, covers the drivetrain for a long time. Smashing the gas is hard on these components. Does the Sonata have this? I don't know. But if i worked at Hyundai, I would make sure the computers had torque management.
Not to say that cannot be overcome, but it will cost. I had my truck retuned to drop out the speed limiter, rev limiter and removed torque management. There are people who come to you to retune the vehicles for this, as well getting it dyno tuned. Now, there's handheld tuners/programmers, but the general opinion is they are very costly for what little they can actually do for you ( except for diesel vehicles ).
There should be a feature like Vehicle Stability Assist or something like TSC that you can turn off, it's basically a feature that prevents your wheels from spinning out. So if you wanna smash the throttle, then you gotta turn off that feature first.
I had my 09 Sonata back to the dealer several times for the hesitation problem. They actually told me unless there is a code (check engine light) do not bring it back again for this problem. They found no issue wih the scans and tech test drive. Each time I left the dealership I was about 5 miles away it started again at the first traffic light. I am fearful that if I continue with this issue I will get in an accident someday.