Would be so great to see this done properly in software. I just don’t see a good way it can be done yet, nor have I seen a good reference implementation. Multi-level projects are not the solution here, I believe.
For me this problem is currently solved with a pen+paper flowchart. It’s easy to create, it’s easy to throw away when plans change. It’s easy to create actionable Everdo projects based on such plan.
The way I see it there are two modes in GTD: planning and execution.
Everdo focuses on execution and has few planning features. The user is “supposed to” add short-term goals (aka Projects) and those are manageable as flat lists of tasks. Larger scale plans need to be kept separate and used as a source of projects to add to Everdo.
Project organization in multiple levels is a planning feature - it adds nothing to aid execution, but it adds complexity in a huge way. And it’s insufficient for planning either, unless it also handles dependencies between projects properly and has great visualization of both project structure and dependencies. Would love to see/try to use something like that.
I would really appreciate any pointers to products that do this right in your opinion. In particular it’s very interesting how dependencies between projects and tasks are managed across multiple levels.