IMHO the letter focuses too much on capabilities consistent with the recent past, while any public policy intervention should be focussed on bringing the future sooner.
The letter argues for a purchase incentive for EVs with "minimum all-electric ranges of 50km", if you want to change the world the focus should be on the next generation of EVs (model 3, Bolt, Leaf) and the goal of a 300+ km BEV at a cost in the $30k range.
Similarly, the focus on incentives for a general term like "DC fast chargers" rather than on "chargers that deliver at least xx kW" seems inutile given the availability of low-powered DC chargers. A 25-50 kW charger is not going to change long distance travel, as only enthusiasts are willing to drive 2 hours (230+ km) and charge for 1-2 hours (25 or 50 kW charger for a car using 200 W/km) in order to drive for another 2 hours. In my opinion, wide scale adoption of affordable BEVs with a 300+ km range for long distance travel will require chargers with the power to allow an individual to drive for two hours and charge in less than 30 minutes in order to drive for another 2 hours; in this regard a 50 kW DC charger is woefully under-powered for a car with a 300+ km range.
So let's focus public policy on what we need for wide scale adoption of zero emission vehicles in 2017-18, when Tesla, GM and Nissan are all aiming to deliver affordable BEVs with a 300+ km range.