1. The innocent login form
is broken.

2. (most sites are not so helpful with the user and password)
If you aren't a registered user, or if you forget your username or password, Drupal makes you start over.
(most sites are not so helpful with the user and password)

3. Why isn't the
username from
before prefilled here?
or here?

4. Those are minor usability issues.
Compared to the fundamental workflow problem of inviting people into your site, letting them get involved in the content, and then when they go to reply to comment 43 on a post in section Z...
Or are about to sign up for an event...
Or would just as soon *register

5. Drupal sends mixed signals.
Welcoming Users
Drupal sends mixed signals.
"Hey we have all this rich interactive stuff you can do here but you'll have to register first or login or Facebook Connect or OpenID or something but you have to do it first and get it right the first time because you'll have to enter your or username or password over again for each method you try."