search for other messages from author in thread-view-mode
forward attachments
tab completion on labels, contacts
within-buffer search
contact selector in edit-message-mode
undo
maybe: filters
maybe: rangefilter on the initial inbox to only consider the most recent 1000 messages
select all, starred, to me, etc
editing of arbitrary messages
annotations on messages

x word wrap
x background indexing
x auto-insertion of draft messages
x drafts
x sent messages loader
x search: from
x contacts
x tagging for group operations
x view: starred, to me, etc
x pull in messages by subject as well in load_thread_for_
x reply+compose+forward
x resize
x buffer respawns
x readline
x "loading" message
x search: body, to/from, tags (requires: readline)
x highlighting/different color stuff
x config: your email, sendmail, etc
x status: to/from_you, cc_you_others
x status: new/not, important