Requirements gatherer

I think on my next project I'll endeavour to find a requirements gatherer. This is something that has worked out interestingly in our project and I think it is one of the missing pieces in XP.

When you have a customer they often lack the ability to express and prioritize their needs sprint by sprint. They need a grasp of the whole product. They need a grasp of what is important. They need to be able to help the customer prioritize to build a better product.

This is the person that needs to understand the big picture as well as the small. They also need to understand in their bones that development won't be able to build everything the customer believes is essential.