Do you have a user model? Are both your team and the marketing and development teams familiar with it? Is it based on real users, or what people think are real users?
Pick a reference configuration for your current system. What are the various values for the performance factors described above?
What was the last article or book you read about usability?
Where could improved usability help you improve your product or service the most? What is the potential economic impact of this improvement?
What kinds of feedback does your system provide? How do you know that this feedback is helpful?
Ask your marketect for a copy of a recent RFP and her response to it.