Merge pull request #33 from AusDTO/fixes#32

Narrowed conformance criteria, emphasised simplicity and eco rationale

principles/empathy.rst

@@ -3,8 +3,12 @@ Developer empathy
 
 **Design with developer empathy**
 
-Developers are users too and the same principles of user-centred-design apply to the development and publishing of APIs – except that your user is a developer that wants to consume your API rather than an end user that is a customer for the government service or data.  Most of the other criteria in this guide are traceable to this criteria.  
+When it comes to APIs, developers are your users. The same principles of user-centred-design apply to the development and publication of APIs (simplicity, obviousness, fit-for-purpose etc).  Most of the other criteria in this guide are traceable to the principles of good design. Perhaps the most important criteria to be mindful of is *simplicity*: as with any other product, people simply won't use something if it is hard to use. 
 
-All Government APIs will be published to a central service register as described in Building and publishing APIs.  The service register will provide a mechanism for developers to provide feedback on APIs.  An API that is consistently rated as hard to use should be considered defective.
+Hard-to-use APIs create bad public policy outcomes:
+- Potentially significant economic value will remain undiscovered or unrealised
+- Secondary markets that form around APIs (e.g. automated tax reporting software) will be less competitive, and therefore less efficient (API complexity creates barriers to market entry) 
 
-**Conformance Criteria:** less than 20% of feedback rates the API as poor.
+To ensure dicoverability and accountability, all Government APIs will be published to a central service register (as described in Building and Publishing APIs secion [insert link]).  The service register will give developers a mechanism to provide feedback on APIs.  An API that is consistently rated as hard to use will be deemed defective and should be remediated.
+
+**Conformance Criteria:** less than 20% of feedback rates the API as hard to use.