I don’t think it’s “missing” those tools - I think it’s not trying to specify those tools. It’s a system for personal productivity, not a corporate project planning tool.
Do the individual people on the team leave meetings with assigned tasks, and know what the next action they - as an individual - need to take? Defining and tracking that individual task / next action is GTD’s domain.
Which is probably why GTD doesn’t actually ask you to figure out how long a task will take. And it doesn’t ask you to waterfall plan your project. It just asks you to get clarity about the outcome you want to achieve, using whatever tools you need to do that, and then identify the next thing you need to do to move you closer to that goal - however that works for you in your world.
GTD doesn’t replace the other tools that clarify your objectives, manage multi-person projects, etc. It’s explicitly not designed for that, and DA refers to the need for other tools in the GTD book:
Organizing usually happens when you identify components and subcomponents, sequences of events, and/or priorities. What are the things that must occur to create the final result? In what order must they occur? What is the most important element to ensure the success of the project? This is the stage in which you can make good use of structuring tools ranging from informal bullet points scribbled on the back of an envelope to heavy-horsepower project-planning software. When a project calls for substantial objective control, you’ll need some type of hierarchical outline with components and subcomponents, and/or a Gantt-type chart showing stages of the project laid out over time, with independent and dependent parts and milestones identified in relationship to the whole.
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The final stage of planning comes down to decisions about the allocation and reallocation of physical resources to actually get the project moving. The question to ask here is, “What’s the next action?
Ultimately, at the project level, GTD insists that you plan and clarify objectives to the point where you can identify “next actions”, which you (or others) can execute. It’s not really a set of tools for doing that - it’s a basic set of principles.
Once you have your projects and your next actions, GTD on the personal level leads you to having an inventory of the things you’ve committed to do, and next actions to move those projects forward.
I do programming for a living, so I get it. Targets change. Things get re-specced in response to dozens of things. But ultimately, there has to be something I’m driving toward, and something I’m planning to do to get to that goal.
I would suggest that a project doesn’t ever have to be completely “clear”, but it needs to be defined enough that you can figure out how to move toward it. And once you figure that out, you should be able to get clarity on “what I do next”.