We can have interesting discussions about the value of business cases but in the end we know that we need one. It might be simple or complex, anyhow it shall be solid and trustworthy. We have built dozens of business cases in all forms and if there is one thing we know for sure: don’t make it your private party.
Your initial calculations gave you the confidence to continue your innovation. And now it becomes time to involve other colleagues, departments, stakeholders to provide their input and discuss calculations. So they can support your plans when it comes to critical phases such as go/no-go decisions from the board and actual implementation after the green light has been given.
This also involves realistic market data, discussions with sales and customers and a top-down as well as a bottom-up approach to make sure we are not loosing ourselves in the parallel universe of spreadsheets and powerpoint.