> Proposing fundamental product changes takes solid grasp of what is called "product architecture" in the article, i.e. precise understanding of the concepts involved and the intricacies of their interaction.

That's exactly the point. Assuming your product will be used by humans, a designer (a real designer; not a dribbbler pixel-pusher) is way better equipped - in terms of methods for understanding users and context - than a engineer or a manager.