We had the update done last week. Before the update, we were charging to 80% every day and had gotten only one low battery warning in 500 miles of driving, which came on with 19 miles of estimated range on the display. Since the update, we have had estimated range down to 12 miles and have yet to receive a low charge warning again, so they definitely put more reserve at the bottom, and changed the threshold for the first warning (I assume to 8-9 miles, as people here have reported).
After the update, we made our first long trip in the Leaf on Easter Sunday, and charged to 100% for the first time in anticipation of needing the full range and possibly more. We traveled from La Jolla to our in-laws house in Alpine, which included climbing from sea level to 2000', with 90% of the driving at freeway speeds. I set CC at 65mph and slowed a few times to take advantage of drafting behind slower trucks, but generally went the speed limit the whole way, not babying the car (although we used ECO mode throughout, as we always do, and no climate control was necessary, as it was a pleasant day).
We arrived in Alpine with 42 miles on the trip meter and 30 miles estimated range remaining on the display. I knew i would get back some range from regen on the descent, but to be safe, I put the L1 charger on the car while we ate dinner and visited for 3 hours. The top bars of the SOC meter did seem to drop faster than usual, and since we had started with 103 miles of estimated range, had driven only 42 miles but used up 73 "estimated" miles, I chalked up the 31 "phantom" miles that disappeared as due to the high average speed and the elevation change.
On getting in the car for the return trip, the range display showed 41 miles estimated. As soon as I shifted to ECO mode, it displayed 47 miles, so I gained somewhere around 15 miles from the L1 charging. We set out for home and on the descent from Alpine, the range estimate got as high as 57 miles even though we traveled 10 miles during that time. I knew we would safely make it home then, and we did, arriving with 14 miles of est. range left (last 2 bars still lit) after driving 83 miles total (mostly freeway) miles. It appears we MIGHT have made it all the way there and back without any opportunity charging, but it would have been close, since the amount we gained from charging at mid-trip essentially equaled our ending charge, and we certainly would have gotten into the low battery warning stages at the end if we had not reduced speed or something.
Overall, it was acceptable and normal performance as far as the range goes, including quite a bit of climbing and without any real hypermiling--totally comparable to the range we were getting prior to the update, so I don't believe there was any "reduction" in range caused by the update, just a shift in the way the the range is estimated, weighting it towards the bottom of the scale. I don't mind this at all, and will adjust to the new "reserve" quickly, I think. I don't understand anyone's resistance to doing the update, especially if there is still a chance that the A/C problem could effect your car w/o the fix. You're likely to get it one way or another in the future, or be left behind, so just go have it done.
I don't think there is anything to fear here. Future updates/revisions are bound to happen, and may introduce features/fixes that you might want to have. I'm not buying into the "conspiracy" outlook on the update, and am just going to believe that the Nissan engineers know what's better for the car than I do. If there's another one soon, I'll be getting it too.
TT