Call them what you will, “Truths”, “Product Owners”, “Business Representatives” etc. If you’re doing agile, they need to be very opinionated and focussed on what they want from the solution. Otherwise progress will be difficult, and the end result unpredictable.
The same is true before the project gets underway. When IT asks for the money on behalf of someone else, you can bet that the commercial reasoning will not be as strong as it should be, and the product owner uncertain about what it is they really need.
In my opinion the most successful projects (and solutions) always have confident, focussed Product Owners. In fact, it could be argued that its best not to start an agile project without one.
Personally I’ve ever actually worked on a waterfall project, but perhaps this is one area where waterfall had a slight advantage? The up front documentation probably gave you a chance to build consensus and ‘forge’ a Product Owner if an obvious candidate didn’t materialise naturally.
What do you think?