I think you'll see a lot of Lobbying going on by Tesla, Nissan, and Chevy once the tax credits start expiring. They were the ones who were the trailblazers and let the revolution. They also definitely needed the tax credits to offset the early added expense of the Li-Ion batteries. I don't think its right to let them take a big hit when the competition can just swoop in sometime in 2018 and take advantage of greater tax credits than them. I would hope that you would see the government revise the credits in the next couple years to either extend them for all, or come up with a new methodology of applying them that doesn't leave Tesla, Chevy, and Nissan out to dry. Although the prior poster got on my case about it, I don't think being one of the first people to reserve a model 3 is that bad of a move from a financial perspective, given this tax credit situation. I do however think that the announcement of the Model 3 is going to take a serious bite out of the Model S sales for Tesla. You're gonna be hard pressed to get someone to pay $75K for a Model S 70D when they can just wait a year or so and get a Model 3 for $40K less. Sure it won't be as fancy of a car, and likely not as quick, but I doubt that it will be too far off the mark, or at least not $40K off.
As far as Leaf 13-16 resale values go, I think that you will see a small rise in those one the tax credits go away, especially if Nissan starts selling 30KWH packs at $5500 or so to all 11-16 owners. However, I doubt there will be that much of a bump. I think that given the reliability of EVs, and the eventual decline in replacement battery costs, the floor for a used Leaf is somewhere around $8K. I think this will happen once they have Leaf Gen2 available and they've cleared out most of their inventory on the 2016 models a year or so from now. One thing that I'm considering instead of buying a Model 3, Bolt, or Leaf 2, is to see what kind of prices they start selling the 2016 SV/SL at around this time next year? Once we know everything about the Model 3, the Bolt is hitting dealerships, and the Leaf 2 is a few months away, I think you'll see Nissan really wanting to move their 2016 models. You may be able to get a really ridiculous purchase price on them, and for us CA people, you may still be able to get the $2500 state rebate as well (assuming it doesn't run out of funds by then). So much to consider....