The Custom Fields are great, but it would really be helpful for the End User to be able to see and input information into custom fields as well. Being able to set which field is required would be a great addition to that as well.
An example would be that in our school district, we have multiple sites and have teachers coming and going every year. Allowing us to add a custom field for "Site/Location" and then the end user being able to put their sit in that field would be very beneficial.