Contacts need a scroll bar or alphabet list so contacts can be accessed quicker. It takes too long to search through contacts.
When I access the contact feature I get a list starting at "A". I have to slowly scroll through all of them to get to the one I want. Sometimes I'm unsure of spelling or how the contact is listed in my contacts. A scroll bar allows me to pull through the contacts with greater speed. See the Android contact App for example. Pretty basic stuff, not sure why MS hasn't mastered this yet.
Daniel Quintero commented
This is needed!