The asterisk which marks the password field as a required field is missing from both the Clean and More themes in 3.3, while the new exclamation point image is present in Boost.
Confirmed in both Firefox and Chrome.
This was reported to me by an accessibility tester as an accessibility violation, since having the words "Click to enter text" in red is not accessible compliant for those with color blindness issues to mark this as a required field.
The asterisk should be restored as it was in earlier versions, as this is the consistent marker for all required fields for these two themes.
1) Enable Self-registration on the site with the default theme Boost. Logout and go to the /login/signup.php page. Verify Boost shows the proper theme indicator for password as a required field.
2) Login as admin, set Clean as the active theme, flush the theme cache. Logout and go to the /login/signup.php page. Verify that the asterisk is missing from the password field, but present in all other required fields.
3) Repeat step 2 using the More theme.