I agree with all the points that everyone in this thread has mentioned so far. The planning phase will down the foundation of how you will tackle the project. A poorly executed planning phase may cause the project to fail, face issues such as delays, or will downright not be profitable at all for the company which cause layoff or much more. So another aspect that should be important is to determine based on what the team is given (budget, resources, previous experience) if the product will be profitable based on what the team can design and develop. There is no point in continuing a project if it will not be worth it for a company, even though it sounds like a great idea.