1. It's not great having a 404 page not found when trying to access a protected page. It would be better if their was an option to set a redirect for when someone tries to access a page they don't have permission to view. This way they could be redirected to a page with a login form.
2. When users log in it would be good to be able to redirect them based on group. Say you create a members hub page with links to other members pages. When a members group member logs in it would be good to redirect them to a selected url, in this case the hubpage. This would be a powerful feature to add, perhaps a wordpress page / post dropdown on the group edit screen