The vision needs to motivate the other senior executives to trade in their proprietary, functional agendas for a piece of a bigger idea. The vision needs to be articulated in a way that allows everybody to see their ends in the CIO's means. If this sounds difficult, it is. In fact, it is the only part of your job that nobody can do but you. Hiring consultants to set your priorities is like letting your mother pick your spouse.
Input is one thing, abdication is another.
You know what is best, and you have to live with the result. One CIO of a large retail company with whom I worked delegated planning to consultants who worked independently with his boss and senior management. Needless to say, the consultants focused on the boss's priorities and the CIO was not long for that job. The focusing process will take a lot of time. You are going to have to dedicate at least a day a week, probably more like two, for the rest of your professional career.