LTLFT:
1) The lack of battery checks has made no difference and Nissan (has) been replacing degraded batteries (2011-12) anyway when qualifying at 8 bars and under 5 years/60,000 miles for capacity warranty. There has been one case with BBB that no longer had a capacity warranty, and having ALL battery checks, did help them to get a new battery under a material defect warranty.
2) Nissan capacity warranty on 13s and newer is to repair to a minimum of 9 bars by swapping out modules with reconditioned battery packs and as you correctly stated are not a part of Klee v. Nissan where they have to be replaced with (new) for class members. They may start repairing/reconditioning them in the future for 13+.
3) Lizard batteries do not hold up better in hot climates. You are in a hot climate. Maybe when buying that used car, If it was previously from the North, It may be better.
4) Other than the battery degradation, most are finding out that the cars are very well put together and holding up well.
Good luck! We love our two Leafs, but rapid battery degradation, not so much.