I went all over the internet to find a fix to this problem and couldn't find a single one. And, I just fixed it. My 2008 Nissan Versa had a key that wouldn't fully turn to the lock position in the ignition (to get it out). I'd just have to wiggle it while pressing backwards to get it to eventually get there.
So, first I took off the middle console panels/plastic pieces. I got down to where I could see the gear shifter. On the right passenger side you can see a cable that comes into the assembly (it connects under the dash into the ignition and prevents the key from being removed when the car is not in park). So, after looking at this cable and seeing how everything works (and watching youtube videos that didn't quite address the problem), I found that if you pop the cable from its little slot (just above the floor), it becomes more flexible/loose. Then, you just rotate out the end of the cable from the gear shifter unit. The end is grey/silver metal. Once out, I just had to losen the plastic connector so that the metal piece sticking out was shorter. By doing this, it puts more tension on that cable that goes back to the ignition, and when its in park, tells it its ok to have the key removed. I tested it out and put everything back and now it works fine. I saw folks cleaning dust and grime out, mine didn't really have that problem, just needed to be adjusted. I don't know if it was out from the start or if it got out of whack along the way, but it now works like its supposed to.
i think its part of the drivetrein or drivetrain warranty and its usually longer than the regular 30k miles warranty 
