The following screens would be much more intuitive:
0. Overview (statistics: #open projects, inbox size etc.
1. INBOX (show open and tickled thoughts)
2. Vertical view (shows projects, actions, waitingfors in a tree view. Shows open, tickled and done items)
3. Horizontal view (shows open and tickled actions, filtered on context)
4. Waitingfor (shows open and tickled waitingfors)
5. Someday/Maybe (shows thoughts, projects and actions on someday/maybe list in tree view)
6. Archive (all done actions, projects, waitingfors and processed thoughts)
Some global keystrokes:
From all screens:
A : add action
P : add project
W : add waitingfor
from INBOX screen:
^a : transform thought to action
^p : transform thought to project
^w : transform thought to waitingfor
The overview screen could be replaced by a calendar screen, which defaults to 'today'.