Here is my take for what its worth - Great products require great understanding: The designer needs to understand what can be engineered, now, what needs to be invented, and what can only exist in the future, and an engineer needs to understand what the designer wants. And both teams or individuals are responsible for the process and outcome. If you have a flimsy designer that makes everything look pretty on paper but fails to communicate the entire picture, the engineers will inevitably produce sub par work, not because they're bad at their job, but because you did not give them enough to work with, unless you have visionary engineers with a foot in the design department as well. Then again if the engineers only think code code code they will fail to meet the designer where it counts and again the product is sub par. They are 2 parts of the same creative entity, one that lives and relies on communication and understanding. This is unlike the "well oiled machine" where each person or team resembles a mindless cog in some contraption... These are companies that do not understand the ultimate relationship between designer and engineer. It takes a designer with a stubborn focus on the big picture and a razor focus on the tiniest details along with an engineer of godlike skill to not just solve the puzzles set before them, but solve them intelligently (there is a huge difference), while keeping an eye on the final product. The two parts should always demand validation in their understanding of what the other has communicated.

Build a team that does not simply 'do', but a team that thinks, communicates, and understands; and create an environment that fosters this relationship.