An actual inbox requires many clicks to clear all unreads, assuming you actually read them. What I'm proposing clears all unreads with one click.

Alternatively, just have an asterisk to indicate that there are new submissions you haven't checked out yet:

  new* | threads | comments | leaders | jobs | submit

That's probably the most minimalist incentive you can give to increase New pageviews, and fairly easy to implement. (Edit: updated the original post with this suggestion.)