A couple of my clients asked me why it is not possible to send the user the password he has in the system as a lot of other community sites are doing. I explained that for security reasons we do not store the password in plain text in the database and they argued, why bother if other sites don't. Furthermore a couple of times it happened that someone reset the password using the "forgot password" link so the user could not login again (until he checked his e-mail).
I would like to have a parameter in acs-subsite that allows support for plain text passwords. As for the implementation, this will require a TIP, but maybe you have already some ideas you want to share.