Sometimes it isn't enough to ask people what they want. They can tell you what they don't like, but they often have trouble telling you how to fix it. Then you have to be sure that the fix for one person doesn't cause problems for someone else. In this case, the reason the company wasn't using Inventory was that they found it too complicated and cumbersome. There were too many features they would never use. Theirs was just a simple business.
That's how the role tailored client was born in NAV2009. Every person has their own roll to play. Each person needs access to different features. Jumping around between menus just wastes time and makes the system look complicated. The lay out of the options should tell their order. People should be able to tell at a glance how many transactions they have waiting for them so they can decide what to do next. If something isn't being used, it should be taken off the window. Even if you are filling in for someone else, it should be clear what needs to be done.
Sometimes important steps are taken without any technological wizardry. Sometimes all it takes is a watchful eye and a curious mind.