The list of admins is perhaps better suited for a template placed on a side of the front page. As for the message wall thing, I don't know if we should do a rule about it. I am not used to let blocked people write stuff on their message walls because it usually ends up in insults or annoying pleading and in some cases even a weird mix of the two.
I think it is better to have each admin block people as they please without specifing anything. Anyway, I didn't know about this peculiar custom around here until I read that thread on that guy's wall, about a Sonic videogame page been deleted for being self-centered.
Is this a common thing on these wikis?