I think that there should be more front end features.
Mailing lists should be possible to create from front end, not only from admincp. Of course, this ability is in relation with categories I suggested in this thread: Mailing lists categories with their sets of rules and their links In this way users would be able to create its mailing lists and use them.
But even now I think that we could be able to manage mailing lists from front end.
For example, in this mod on vb.org almost all things could be done from front end. This is of course controlled by usergroup settings, but you don't need to go to admincp to manage every aspect of mod. This is very useful. And would enable that other usergroups could use this mod more effectively and productively, even with admin rights is much easier to control something in front end.