Every last problem of sudo is taken seriously? Did you know that if
someone has limited access, e.g. the right to install standard
packages, then it is easy to leverage that to get complete access.
Various packages run programs in $PATH as root, Firefox comes to mind,
so just prepare $PATH and sudo apt-get install firefox.

Sudo leaves
the user's $PATH and the rest is just a matter of finding the right
exploit.

Was open for years, may still be open.

Arnt