Hi, I wrote this blog post.

We were trying to keep our API surface area small with one way to load data into components, but you're right -- we should probably /also/ add a ES6 base class as a second option, and let the people choose which they prefer.

A lot of React developers still prefer mixins -- react-router recently switched from mixins to ES6 classes and then changed their mind "until ES6 classes have better answers to replace what mixins do (like decorators).": https://github.com/rackt/react-router/blob/master/UPGRADE_GU...