Would Like Video
In this video Dr. Abigail Hirsch demonstrates to participants in a live workshop, the reasons for using would like statements rather than don't want complaints.
In brief, would likes are positive and forward moving. Don't wants, by contrast, are negative and confusing.
You will see the difference when you watch class members try a drill for practicing this skill.
TIP: To maximize your learning, once you understand the drill try pausing after each statement and thinking how you would answer. Then compare your answer to that of the class participants.