It depends on complexity, but I think it's more of a situation akin to refactoring or rewriting a complex code base. A total rewrite is always an attractive thought, but a real focus on continuous refactoring in smaller portion at a time is often lower risk, lower cost, and faster in the end - and I suspect it's the same with large bureaucratic processes too. It's also a way to sharpen the skills of the organization in small steps with lower risks for failure (and improving future project steps...).