Push the ESC Off button, and confirm the stability control is "off" when the indicator lights up in the instrument cluster. Then try accelerating from a stop again and see if it still hesitates.
Edit: if the hesitation you mentioned is at speed and it's taking a while for the transmission to downshift, trying draining and re-filling the transmission a couple times using a full synthetic fluid compatible with SP-III (will say so on the bottle).
I've driven a few Hyundai's with the 3.3L and know exactly what the OP is talking about. They have terrible throttle response...just enough to make driving them feel sort of awkward and harsh feeling (Head snaps back when it finally decided to go).
For some reason the response in the Electric Throttle Body in these cars is terrible. My 2.4 isn't as bad, but I still will sometimes take off from a dead stop a little harder than I should because I keep pushing on the accelerator expecting the thing to move.