Besides the lack of detailed documentation around the REST API, given its importance as a major entry point for apps, it needs to be treated with more respect as a service offering. It's currently being updated in CUs and on SharePoint online without any notification of the changes being made (such as the $metadata endpoint appearing - was it in the August 2013 CU for on-prem?). We either need it to be released in a non-breaking change model (URL versioning such as the Twilio model), or messaging needs to be improved so we know when things are going to be changed. Having a log of changes that have been made to date would be helpful, along with understanding what changes are currently in the queue. For example, I would LOVE to know if the end game for the _api endpoint is to finally be a first-class OData v3 endpoint sometime soon.

Angular2 provides an excellent user experience, especially when tied to Bootstrap (v3 or v4) suitable for creating immersive experiences where the whole of the SharePoint chrome is replaced (other than the top bar).

However integrating it with the SharePoint REST API framework is cumbersome and unless extensive work is undertaken to mock SharePoint the unit testing and rapid deployment is very unpleasant if possible at all.

The SharePoint framework provides a rapid deployment and unit testable mechanism for developing SharePoint functionality but is limited to single web parts.

Please extend the model so that it can be used to create single page applications in the framework of the developers choice.

Trying to learn a new framework is hard enough when the documentation is complete. Sadly the SharePoint Framework Reference at https://dev.office.com/sharepoint/reference/spfx/ is not even close to anything that could be considered thorough. Much of it consists of a bare minimum that describes what an item is but not how or why you would want to use it. Some items are described with the name of the item itself, a circular reference that informs no one of anything. Many items have no description in the description column for the item. And far too many links land on pages that only say "Document not found."

For a company the size of Microsoft this is disappointing and distressing. Please:
1) fix the broken links
2) ensure that the description of each item (class, method, property) is clear, correct and meaningful
3) provide relevant, meaningful examples of usage, in Typescript, that shows the necessary import statements to use the item, an example that makes real-world sense, and comments that explain not only the usage but also the expected outcomes of the use of the item.

Complete, accurate and useful documentation is the hallmark of any enterprise production-ready software development platform. Thanks for listening/