It's been very interesting to read most of the prior entries on this thread this evening, since I just had a new main battery installed this week. I did not know Nissan was in the process of essentially capitulating to the demands by owners that all warranty claims be fulfilled only by totally new batteries that would restore capacity to 12 bars, rather than attempting repairs to the original batteries or replacing them with "remanufactured" ones that restored capacity to only 9 or 10 bars.
From other threads I've been reading since I made my warranty claim a month ago when my Leaf's battery capacity dropped to 8 bars (at approx 31,000 miles), I assumed a new 2015 battery would be installed since that was what other claimants had been receiving. However, my dealer's service manager was unable to get any confirmation from Nissan corporate about what version would be sent. When the battery arrived, we examined it and agreed that it LOOKED brand new, but couldn't find any label or markings that would confirm it actually was a new 2015 battery. After installation, I do have 12 bars of capacity again and the GOM mileage estimates are similar to what they were when the car was brand new.
By the way, I had no trouble getting the warranty replacement accomplished, even though my lease was going to expire on March 8th. In fact, the no-cost installation of the new main battery together with Nissan's offer of a $6,000 reduction in the end-of-lease-buyout amount led me to purchase the car instead of returning it (which I was absolutely dead set on doing just 2 months ago).
What I still don't understand is how many of you have driven over 40,000 or 50,000 miles, in geography far more challenging than flat south Florida, and still have 9 bars (or more) of capacity left. From my experience with capacity loss for 3+ years, if I had tried to drive my Leaf another 10-20,000 miles with the original battery, I would have had only 6 or 5 bars left!