You Need a Static Organizational Model
Most organizations are organized around one static model, the resource team. This is our much beloved organizational pattern where we pull all the BA's into one group and all the developers into another group. People are assigned to project teams, but the resource organization is the strong side of the matrix, the project organization is the weak side. Resource teams don't deliver value by themselves.
Agile asks us to organize around the parts of the business that deliver value, and in common practice, that is usually the product. It makes sense, we make products, let's organize around the stuff we make. This is where we get the whole, give the team what they need to deliver, and they'll give you working software at the end of every sprint routine. Single PO + Single Team = Delivered Business Value.
That works awesome in small product driven organizations. In the complex organizations we've been talking about here, this approach is problematic. Why? Investment is not always level across products. Sometimes I need a full staff and sometimes I don't. Sometimes I want to improve one set of product capabilities and just keep the other capabilities in more of a steady state.
Uneven investment in products over time is what drives our obsession with project work. We know that we don't need the same people doing the same thing all the time, so let's deploy 'teams' to go build some value for us. When they're done, we can break them up and have them go do something else. From an agile perspective, the problem is that this approach doesn't keep teams together over time, and that makes it really hard to really do agile.
I'll admit, you could create multi-disciplinary teams and run your project work through these static teams. This is on the right track, but still breaks down when the skills required project to project ebb and flow. I'm all for building teams around specializing generalists and bringing work to teams, but in complex organizations it is a stretch that every team is going to have every skill they need to do every project.
So... back to our static organizational model. If we are going to keep teams together, we need to organize the teams in our complex product organization around the things that aren't likely to change over time. We need a static model for the organization that is resilient. One that reflects the core delivery capabilities of the enterprise, capabilities that can be staffed and deployed to solve specific business problems
In our complex product example, the delivery capabilities might be the various products delivered by the organization. The services they provide to external customers, or to other internal products, become the capability the organizations is expecting them to deliver. A capability could also be something like marketing, or sales, or support, or even some external service provider that you depend on for a fully functional product.
Before you begin your agile transformation, you need to think about your organizational structure. Ask yourself if you are building teams around stuff that will predestine them to be broken apart when the work is done. Are you piloting something that has no chance of long term successes when it get's out into the wild? It is important to understand what the non-transient, static model for your enterprise looks like, first.
Then, and only then, should you decide where to pilot your first agile team.