I do not understand why evolution is using "n" as shortcut for next message.
This task can be much more easily (and naturally) accomplished using the down
arrow. Instad evolution is using the much more complex (and not so much
intuitive) "ctrl-]" as shortcut for next unread. 

I'd like to have a simpler and more natural interface to the next unread
operation, like ad button on the bar, and a simpler shortcut: "n" would be the
natural choice, as also Pan adopted it (using arrows to do next and previuos),
but any single stroke would be better than "ctrl-]". Using the same will be a
bonus also in consistency.

If you have threaded messages next unread is a much more common operation than
simply next, and if you don't have there are no differences. Having already the
up and down arrow to navigate next and previuos email I do not understand the
need to duplicate the behaviour on "n".

I would be useful also to have a behaviour found in thunderbird, that ask if you
want to switch to another folder with unread messages, when there are no more
unread messages in the current folder.