A 40-block area on Manhattan’s west side is a major opportunity for redevelopment, writes Nicolai Ouroussoff. But “despite the tinkering, the city is left with a vague, crudely executed master plan whose main selling point is that it gives developers the freedom to articulate their own visions. Even with a few interesting flourishes, it essentially relies on developer-driven planning formulas. What’s missing is a voice that could give the plan a cohesive and vibrant identity.”