I think `joshguthrie` means something along the lines of this:

http://harmful.cat-v.org/cat-v/

I think `su` is pretty good as-is, but sudo has a bit of feature creep. For example, I don't think these belong in sudo (taken from Linux):

-e: edit something

-l: list allowed/forbidden commands

-p: change prompt

Ideally, sudo would just run as root and su would just switch users. Then instead of:

sudo -u some_user cmd

You'd do this instead:

sudo su -c "cmd" some_user

Su only does one thing (switch users, -c for one-off cmd) and sudo only does one thing (change to root). Currently, both "sudo -u some_user cmd" and "sudo su -c some_user cmd" accomplish basically the same thing, which is a sign of feature creep.