Many approaches to ERP focus on "requirements" which are not connected to the business strategy. If you're familiar with balanced scorecard, the connection of project indicators of success with business indicators of success starts here.
- What capabilities will be needed by the business to fulfill its strategic objectives. If the IT system is not strategic and is tactical then another approach is needed.
- With the capabilities in hand, what trade offs are possible between cost, schedule, capabilty, and the technical and operational requirements that must be implemented.
- What is the seqeuence for the deployment of the capabilities?
- What is the budget for each capability?
- What is the expected business value once this capability is in place and operational?
- What is the confidence intervals for all variables in the project - cost, schedule, technical performance and value? If these are not know, you're likely going to be over budget, behind schedule, have disappointed stakeholders before you start. If they are known, apply some modeling processes to determine the all in benefical outcome of the project. That is we're good on cost, schedule, technical performance, and capability delivery - all together not just individually.