The problem with centralized privacy-as-a-service is the Fed raid problem. In order to be "fed proof," a service must be sufficiently distributed.
PS: I'll say what has been said again, Lavabit was so close to being wildly successful, it's a shame that an insecure govt leadership decided to squash a thriving venture. Though it was a likely conclusion because of centralized ownership.
The problem is not limited to any specific government; the problem is that you are doing something inherently insecure when you allow a service provider to generate, store, and utilize your private keys. Exploits by law enforcement are not the only problem -- spies, criminals, etc. can also exploit the weakness.
PS: I'll say what has been said again, Lavabit was so close to being wildly successful, it's a shame that an insecure govt leadership decided to squash a thriving venture. Though it was a likely conclusion because of centralized ownership.