Contexts for Next Actions are a MUST
Organizing next actions by context is SO much of the magic of GTD. In your app it is entirely missing. "Areas," or "areas of focus," are a horizon of focus ABOVE projects; they are a wonderful way to group your projects. So I like that the feature exists. But areas of focus are NOT the primary GTD way to differentiate between next actions. That's what CONTEXTS are for. There is a fundamental difference here, and it has to do with the 6 horizons of focus; the reality of life is that most of it is on the "runway," where life is coming at you too fast to continually look at it through the higher horizons of focus. You can navigate the runway much better when using context designations for next actions. This concept is FUNDAMENTAL to the practice of the GTD methodology. If you could include this, you would have an incredible product!! As it stands, there is a glaring inconsistency between what your product offers and the actual practice of GTD. Please consider.
We have contexts. We just call them “Tags”.
We use AREAS for the 20K level and Contexts to help at the runway level. We call them tags as they can (but don’t have to be) used for more than context. For example some people will tag people for discussion or who they are waiting on. Tags is a bigger concept, but was implemented with context in mind.
Tiny suggestion: allow users to add tags when looking at the "tags" view, rather than just from within an action/project.