I agree that making the registration page a little lighter by splitting it into several pages with next links at the bottom would be a HUGE advantage.
Because when people see a long registration page they do not even bother to start and when only having to fill out a short registration page there is a high probablitly they never complete their profile in the backend...
So starting by only having to introduce your nick, mail and password and then on the next page to digg a litlle deeper and ask some more optional stuff on the third page of the registration process would be REALLY great as registration process as is in CB seems a little weak indeed when it comes to customization possiblities...