Agreed about --git (and I keep diff.git=1 in ~/.hgrc); unfortunately it is not
the default and I think a lot of new users have no idea they should be using
--git in most cases. Perhaps a documentation/installer issue.

Regarding tools incorporating extra noise: might not be an issue if any warnings
were sent to stderr.

Diff sucks, news at 11. Adding noise to diff output won't help as users won't
see it except in the most trivial cases and tools will ignore it or worse
(existing hg for instance will probably incorporate it in the changelog on import).

Use --git.

$ hg init
$ touch x
$ hg add
adding x
$ hg stat
A x
$ hg di
$

It is misleading for 'hg di' to print no output at all when in fact you have a
modification. Likely confusing for new users trying out Hg by creating empty
dummy files. And some source bases have a legitimate use for empty files; you
would want some notification in diff output (or at least stderr) that they were
being manipulated.

Commands which produce diffs - hg diff, log -p, etc. - should probably issue a
warning if a file addition or deletion was omitted from the diff due to the file
being empty.