annotate: no templates?

[Masklinn]

Is there a reason why annotate does not support templates, and has no
existing support for displaying commit messages (or at least summaries)
in the first place?

Templates support would also help with usernames as currently the only
options are a short representation which displays the user part of the
email address until the first dot (default) or the full username, both
behaviors being suboptimal in some cases (e.g. when before the first dot
is just an initial but full names are seriously long).

Finally, for the readability of the annotations it would be nice if —
by default — blame collapsed changes into a single annotation across a
block of related lines (as I believe is done in git or bazaar), but that
is probably a different issue.