You describe the requirements analysis step which itself is a big issue with traditional waterfall projects. You bring someone (or a team) in from either outsid

You describe the requirements analysis step which itself is a big issue with traditional waterfall projects. You bring someone (or a team) in from either outside the company or inside the company. At that point you are already falling victim to the fallacy that you think you can fully and exhaustively analyse the full problem domain. And even if you think you can do the 100% complete requirements analysis, who says the solution/software you deliver in 3 years from now will exactly fullfil these requirements and - more over - what makes you assume the problems of today are the same problems of the business in 3 years from now?