Priority list:
1-9 as in vim (9=required for next release, 5=would be nice, 1=probably not)

BUGS:
- several tab related commands like :tab are enabled but don't work
- stal=1 doesn't work

(recent CVS regressions):
- 'autoexternal' doesn't work

FEATURES:
9 check autocmd Events - which are applicable etc.
9 edit messages with vim
8 the archives need to be mailbox specific
  - currently it archives mail to the first Archive folder found
7 :set! mailnews.wraplength=140 or similar
6 add a feature to show emails from threads under each other like in gmail