The Tesla Powerwall IS not that big of a deal and not the solution for Solar!
The 10kwh Powerwall is only good for 50 cycles a year! It is more of a house size UPS. The 7 will work for daily use but it is more expensive per kwh than the 10 and even Solar City is not going to sell the 7.
The Tesla power wall battery still sucks. It does suck less than other battery packs but only a little. The big improvment is one of packaging and frankly hype.
I know that this is going to go counter to the Church of Tesla's teachings but even the Model S really does not count. It is a 100K car for the very rich. Another fact is the simple truth that the Tesla car company is not successful car company yet. It has yet to make a profit.
No we do not need to move to low voltage wiring in our homes because of the "success" of the Powerwall. The Powerwall is the the solution to the solar production/demand problem. And frankly in most homes the biggest power users are things like AC, Hot water heaters, dryers, stoves, refrigerators, and so on. All of which work just fine on AC and I for one do not want to have to have a bus bar the size of my arm running to my dryer so it can work on 12 volts.