I actually disagree with your initial statement: “Design is a subjective…”. Design is comprised of processes, methodologies, techniques, all of which aim to solve problems. The fact that creativity, innovation, user input/feedback, among many other factors feed off into this process, doesn’t make this discipline subjective. That statement feeds the eternal concept that Design is Art, which isn’t the case (aesthetic is indeed a Design principle, but it’s one among a series of many). If anything, Design is a discipline that much like alchemy, aggregates a multitude of factors/inputs, to actually produce palpable and measurable results.