I think companies should be required to provide unique passwords. In the past, I have registered with companies for employment who simply use email addresses as user names, and the same default password. I have been very tempted to sign into my colleagues account to see what they have been up to. I think as a matter of security companies should make a unique password for each registrant.
Yes, companies should be required to provide unique passwords instead of default passwords. Default passwords are too easy to figure out, even if it a "secure" default passwords. As soon as you start providing default passwords, a pattern can be built off of past passwords and create a database of potential future passwords.
Companies should use default passwords so that the individual user can make their passwords unique to them. This also will prevent un-warranted users from being able to obtain these passwords once they have been uniquely created. If companies issued unique passwords they could fall into the wrong hands and cause a breech in security.
Users being given unique passwords will likely give them a false sense of security, meaning even less will change it - compared to a default password - and as a result more will likely forget it.
Default passwords usually require changing upon first use, encouraging users to pick something more memorable for them. Unique passwords are often just written down on a sticky note somewhere on the desk, and not changed because "nobody else knows it."