They are calling it "Leaf 2" rather than "Leaf 2.0" so it isn't at all clear from the name that it's all new. If those camouflaged cars are just test mules, it makes little sense, for a couple of reasons. First, why camouflage them? It would be better to just use whole Leaf 1 cars, which are inconspicuous. After all, you don't need to test drive a new nose and tail. The only reason I can think of is if the new motor and pack won't fit into the existing nose and tail, but that doesn't seem especially likely, either - the new nose doesn't seem appreciably larger than the old, and there is plenty of empty space in the tail of Leaf 1...
Finally, since Nissan is competing on price more than on performance, building a whole new car on the cheap, when the existing car's interior is well liked, also makes little sense. Putting a new nose, tail, and dash on the existing midsection does make a lot of sense. That would let Nissan keep building essentially the same body on the same production lines, with only a few new external pieces, and a few (but important) internal parts changing. That would give them a significant cost advantage.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.
The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.