<------ 5 speed A/T
I drove quite a few loaner 7 speed G37x cars (2009-2013) and I hated the transmission from 1st gear to 2nd rolling from stoplight. I believe it doesn't matter if it is a 5 speed or 7 speed. I just hate driving in D for abrupt passing. No matter what car it is. Even my 5 speed EX35 is a snail to downshift in D for passing.
So what I normally do now eversince I bought the Ex35 is to use the Manual mode all the time. When I am driving on the highway and it is clear (less car ahead) i put it in D mode. then cruise normally. When I see a pack of slow cars and trucks less than a 1/4 mile ahead and I know that my speed is faster than them, I switch to Manual mode and select the gear that slightly in the begining of the Ex35 power band. 2.7K RPM. That way, when I need to speed up to avoid any cars that might cut me or whatever, my car will be responsive. It is all in the preparation. Driving needs strategy and you just can't depend on the car alone.
We are lucky enough that we have options to drive in D, DS, Manual mode with the EX. Why not use it's full potential.

Manual mode will fix downshift issue and hesitation.
BTW, DS mode and torque braking from the stoplight is the best way to launch the EX35 hard. You don't really need to floor it right away. Let it slip a bit and gun it!
Maybe you want to do the Nissan pedal dance first and see if the ECU resets. Quicker way to reset ECU vs disconnecting the battery cable.
http://youtu.be/95WszTnphPI
ECU Resetting Procedures
Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.
Operations Procedures
1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.