Everyone is a designer. Get over it.
Daniel Burka

Daniel, I’d encourage you to read Cagan and Vogel’s Creating Breakthrough Products. Cagan and Vogel devoted an entire chapter to the subject of integrated product teams 16 years ago—and there’s plenty of other prior art out there.

Yes, integrated product teams are important… but there’s so much more depth to this discussion. A good place to start is understanding the perceptual biases/gaps between engineers, marketers, and designers. Cagan and Vogel (and Weingart), being the good academics that they are, actually did a study on this subject: “Understanding Perceptual Gaps in Integrated Product Development Teams.”

Disciplines absolutely need to overlap to create great products. Successful team management, though, requires proper understanding of the differences between them. Preserving product integrity from conception to production is really, really difficult. Simply integrating teams isn’t enough. Handwaving away the structural differences between disciplines (perception, biases, responsibilities, power structures, &c.) by placing them all under the nebulous umbrella of “design decisions” isn’t actionable, tactical advice.