SOMEDAY/MAYBE vs. low priorities

[Adam Spiers <orgmode@adamspiers.org>]

GTD methodology suggests having "someday" and "maybe" task buckets for
things which you want to remember to do at some undetermined point in
the future.

So far I have implemented this in org-mode by using SOMEDAY and MAYBE
keywords.  However I have been deliberating whether in fact these
states are simply low priorities in disguise, and whether as a result
it would make more sense to use [#D] for "someday" and [#E] for
"maybe", on the grounds that "someday" implies that you really do want
to accomplish the task eventually, whereas "maybe" implies that you're
not yet decided whether you care too much if it ever gets
accomplished, and is hence lower priority than "someday" (and probably
the lowest priority imaginable, in fact).

Pros:

  - Priorities become truly orthogonal to workflow, e.g. if your
    workflow keywords are PROJECT, PROJDONE, NEXT, STARTED, WAITING,
    DONE etc. then you can mark any of these as someday/maybe
    priority.  This is quite a big advantage AFAICS.

Cons:

  - By default org agenda TODO searches will operate on all TODO
    entries, regardless of priority.  This means that you'd have to
    customise every existing agenda view of TODOs to restrict to only
    priorities #A to #C, which would be very cumbersome.

What do people think?  Are there other pros/cons, and is there a clean
solution to "generally" restricting TODO views to #C or higher
priority?