I agree that the end implementation of a User login and registration system will be highly customized for each application. However, I think there is a TON of

I agree that the end implementation of a User login and registration system will be highly customized for each application. However, I think there is a TON of reusable code out there that is shared across apps: simple things like setting properly salted and hashed passwords, providing a password reset mechanism, and a base user object with permissions and groups. Django gets a lot of this stuff right, what they get wrong is the complete lack of customizability which means you need to throw everything away once you go outside the box. A few simple base classes that could be extended and overridden with custom fields would solve that problem entirely - the reason Django doesn't provide this (IIRC) is because the built in auth system was written before their ORM properly supported inheritance.