At the moment:
1. You can’t ask for more than the email address and the interests on the subscription page --> 2-step-process neccessary,
2. Contacts are not automatically added to the associated marketing lists when they subscribe to a subscription list.
That has to be improved. A simple registration process for users and customers is neccessary so that there is ONE page where someone can register for newsletter etc. AND add his personal data. In addition, when someone subscribes to a subscription list he has to be added to the linked marketing lists. Otherwise subscription lists would be useless.
A solution could be that you can add subscription lists to forms so that there is only one page.
If an automated adding of subscribers to marketing lists is not possible, marketinglists should be able to be added to forms.