It would be great to have a "Next" and "Previous" button to navitage through the tabs. In general I am missing a visual clue for the user when he is proceeding through the form.
Will implement the jQuery bindings for this to be possible, but won't implement the HTML output, which you'll be able to do with a delimiter field to allow for maximum placement and usability. Maybe CB Conditional will provide this again, am unsure at this time.
Also I would prefer a way to freely organize the fields for registration instead of being bound to tabs.
Fact is, that different views are likely to require different organizition of fields. Registration is different from profile and profile is different from userlist etc.
We'll be heading the direction of Layouts for CB 2.1 so it's not likely we'll implement more ordering columns as they won't have much of a purpose once layouts are in.