[Tim Wood]

We have bugs logged for:

<bug://bugs/38655> (mark projects when they do / don't have a next action)
<bug://bugs/38053> (Request: Filter to see only projects with no tasks/single items ("blocked projects"))

so feel free to reference those in feature requests to omnifocus@omnigroup.com. Neither of these are currently scheduled for 1.0, though this would definitely be useful in some fashion.

As the OP noted, one reason these didn't make it in is that this overlaps with project reviews -- a weekly review of active projects will already let you find blocked projects. Now, in some cases, you might find a more timely notification useful, so it would be helpful to explain situations where you'd use this where a weekly review wouldn't be sufficient.