That sounds nice, but Amazon is still a US company, and the US government seems pretty staunch in their view that US law trumps country-of-residence law.
I'm not saying that is what they are doing but it would be a very interesting strategy.
Like for tax evasion vs tax avoidance, law enforcement cannot complain that individuals and companies use rules to their advantage, they just have to make smarter rules.
The point you're making is whether 'state actors' can get into your documents or email. It's a different order of magnitude issue. First, as a company you're going to comply with whatever the law is in the jurisdiction. Second, if you're being attacked by a state actor then you've got major issues. And for many businesses even considering protecting against that wouldn't make sense from a cost vs risk perspective.
In order to make e-mail into a system where two people can communicate in a secure fashion, where no data is stored on or passes through a remote system unencrypted, you would have to re-implement e-mail. And of course there goes interoperability.
Require US companies to follow US law and regulations, across global legal entities, even when the local law of locally incorporated entities is incompatible with US law, absolutely yes, that is required.
Then why the hell would anyone build a company in the US?
Addressing Office 365 Customer Concerns about Data Geo-Redundancy and Location - http://blogs.technet.com/b/uspartner_ts2team/archive/2013/06...
Where is my data? - http://www.microsoft.com/online/legal/v2/en-us/MOS_PTC_Geo_B...
http://arstechnica.com/information-technology/2015/01/amazon...
"Another notable feature of WorkMail is that users can specify what Amazon region their e-mail is stored in. Customers can choose a specific, relatively close data center to reduce latency in retrieving e-mail or for compliance purposes—such as European privacy regulations. The feature means that users won’t get the benefit of failover to another data center in the event of an outage, but Amazon may offer mirroring services later."
That is a big differentiator for many companies right there.