The long names are actually just the only way we can get them to play nice with virtual domains, while allowing multiple customers to have the same listname on different domains (without creating a unique mailman installation for each account or domain).
This is something that's being though about / worked on. Note that you can still send email to "firstname.lastname@example.org" - however it's hard to get the footers / headers customized.
W/r/t the headers, it is only currently possible to turn off RFC2369 (good I can't believe I remembered that correctly... I'm such a dork) headers on a global basis currently.
Mailman 2.1 is supposed to have better virtual domain support, and I think it may be possible to turn off the "list-..." headers on a per-list basis.
I've also looked at sympa a little bit, which has some nice advantages... not sure if we want to rewrite our backend
I'm afraid that any changes to the mailing list service will probably be a long time in coming, as we're all pretty busy right now. Getting something to work is one thing, but getting it to play nice with our backend is another matter.
I believe that the foo-owner and owner-foo are both created because they're conventions of different mailing list systems.
You don't actually have to use any of these addresses; they're just created as part of the default install.