Thanks for your comment and question. Competency modeling is something of an art form, and one is always making a trade-off between getting a good model and managing the investment of resources (money, time, etc.) . The trick is to match the approach to creating a competency model with the demands of the situation. When you are creating competencies for a key role with lots at stake (perhaps there are a large number of incumbents in the role, or it is strategically critical), then it is imperative that you get the competencies right. Similarly, if you are trying to create a competency-based foundation for HR practices, and will be building pieces of your HR infrastructure around the competencies (e.g., performance management process, recruiting and hiring system, development processes, etc.) then it is inmportant to get them right.

I hope this additional perspective is helpful.