We’ve been keen users of Hackpad here in the UK Government for a few years now. We would like to migrate to Dropbox Paper, but it’s not currently accessible using a screen-reader.
We have vision impaired users who rely on screen-readers and we have a responsibility to support them.
We’ve looked at the code and the main issue appears to be that the application role is applied to the entire UI. This causes screen readers to stop intercepting keyboard commands and pass them back through to the browser instead.
The upshot is that a screen reader is stripped of its usual shortcuts and navigational commands, making the app unusable unless scripting is used to provide the expected keyboard support.
Collaboration tools like Paper can have a huge impact on the lives of people with access needs, but only if they're built to support the full range of technologies that people use.