I was experiencing rough and erratic shifts with my transmission, as well as hard downshifts and "engine braking" when decelerating. I had my dealer perform the TSB mentioned by brynomon and I am pleased to report that it corrected the problem with no side effects. My car accelerates briskly with no lag and the transmission shifts smoothly and effortlessly. Thank you to those who posted about the TSB to correct this problem.

 

I have also just had the TSB update done by my dealership. Funny enough, the service writer mentioned it to me before I could mention it to him. Apparantly there have been a lot of complaints about this so this has been circulated through infiniti by now. A week after the TSB and the car's transmission is much improved especially in traffic. The downshifting is also a lot smoother (70%) and I havent noticed any loss of power or loss in the transmission feedback. The famous drone is still there ... but that was always there from before the TSB and is a result of the G going into higher gears I'm assuming for fuel efficiency.