along with optional transparency.
Transparency means that the whole world can see every block - their's and everyone else's.
The "viewkey" concept already exists - it's called a private key. It only has value because it has leverage over a communal resource. Bitcoin already has privacy perfectly worked out using that model. What's missing is that over time, the tokens can form patterns that are identifiable. So the solution to that is to support conditional large scale recycling of the tokens periodically to keep them "fungible" - job done.
Burying the whole blockchain from view is just kissing your entire value proposition goodbye.
What? No, the private key is your funds, without said private key, you own no "x"coins. The viewkey is nothing like the private key, the viewkey only allows a 3rd party to view your holdings, they can't do anything else, they can't even see who you sent (x) amount, or who sent you (x) amount.
You can see every block, you just can't see what's happening(Where the funds are getting sent to, etc). Basically, you see only very general things like amount of coins emitted, nothing specific that would would link "1+1" together.