You had a condescending tone in the first place, so expect to get something in return. Do try to enlighten, not me though, yourself please: the difference between sudo and runas (su) is that sudo uses the user's profile and the permissions system in sudoer, groups, passwd files. It asks for the password of the current user not the one this user wants to be. So, e.g., the root (administrator) password is not neededat all, you may to disable it completely by not allowing to login and still using it. Very nice feature from the security point of view for a desktop. Expect a Windows sudo in next 10 years.
Anyhow, you hide behind a mask and I am not interested to continue either.