Mark,
I'm somewhat reluctant to post, expecting a sentence-by-sentence rebuttal, but here goes…
Planning mode is for manipulating the
hierarchical representation of your projects. It is, at its essence,
an outliner.
Context mode is for viewing a cross-sectional
sample of actions (leaf nodes in graph theory) from your projects. It is, at its essence,
a flat list.
I don't like to quote the gospel according to Allen, but I think chapter 8 of Getting Things Done provides some motivation for the current distinction between the modes. In particular, Allen suggests that one reviews one's lists of next actions by context on a daily basis. He suggests reviewing projects on a weekly basis. The implication is that these are, from the reviewers perspective, separate lists.
Certainly OF's distinction in modes is not strictly necessary, as the overlap in configuration options for the two modes attests. However, I'm also not yet convinced that a single view mode with sufficient configuration options to get all the current views would be any easier to understand. Perhaps a UI mockup would help me see the light. (If the academic year weren't underway here, I might try to mock up
the iTunes-motivated design that I mentioned in the other thread.)
I
am convinced that a Smart Groups style interface would be an improvement over Perspectives. I think Omni agrees and has that in the pipeline for a future version.
(And since we're not going to see a complete UI re-design in the next few days, one tip to keep in mind: Double-clicking the bullet of an action in Context mode will display a new window focused on the action's project. With that one tip, I'm perfectly happy planning in Planning mode and doing in Context mode. Reviewing happens across a variety of perspectives and in both modes.)