TOPIC: "Depends upon" attribute in tasks?

I would really like to see a "depends upon" attribute in tasks (and possibly projects) as implemented in the Linux command line tool taskwarrior (http://http://taskwarrior.org).

Main benefits would be:

1. Linking tasks which depend on other tasks which are not part of the same project - I frequently have tasks in one project which are pre-requisites of individual tasks or tasks in other projects.

2. Specification in detail of the sequencing of tasks within a project.

This could be implemented through an additional status category (working in the same way as "delegated" but allowing the task to be inactive until the preceding task has been completed - although one task would need to have multiple precursors)

This would be a great feature! I want it too!