I would really like more customization options in how the Add New User function works.
I want to be able to make certain fields (like email address, or custom fields) mandatory for all users. If we create a custom field that we need for tracking or enrollment purposes, it becomes completely ineffective if we can't guarantee that every user has it assigned.
I also want to be able to hide fields that we never use (like address) from the form so that our lower level admins don't get confused or overwhelmed by unnecessary information.