Wave Developer API
Create a Wave API as a service. Allow developers access to an API to be able to use Wave's features in separate applications.
As an application developer I want to build an app that could use some Estimate/Invoice/Payment features. Instead of building all of that out myself it would be nice if I could call Wave APIs to handle that so I can focus on the actual niche problem my application solves and release faster. Wave will still be able to handle all the payment processing to make money, my application has a richer feature set with less code to maintain and users get to enjoy a full-featured application.