Something I've noticed on Revenue Cloud projects: nobody sets out to overscope. It just happens because everything's available on day one. Billing, orchestration, taxation, amendments, usage. All there, all reasonable to want, all in the plan by the second workshop. 

Then it's six months later, and sales is still quoting from a spreadsheet.

The orgs that get live fast usually didn't do anything clever. They just picked a smaller starting point. Pricing that doesn't need a human, quotes that go out same day, renewals that don't slip through, a portal so customers stop emailing. That's most of the pain for a fraction of the build.

The easiest way to find your own starting point is to ask what you could postpone six months without anyone complaining. Surprising how much of the original scope survives that question.

If you're interested, there is a session on how the discovery works, plus a customer who went live in weeks and what they left on the shelf.