Some nice naval-gazing about the planning profession, Thomas Campanella writes: Reconsidering Jane Jacobs: The Death and Life of American Planning: Places: Design Observer:
"The second legacy of the Jacobsian revolution is related to the first: Privileging the grassroots over plannerly authority and expertise meant a loss of professional agency. In rejecting the muscular interventionism of the Burnham-Moses sort, planners in the 1960s identified instead with the victims of urban renewal. New mechanisms were devised to empower ordinary citizens to guide the planning process. This was an extraordinary act of altruism on our part; I can think of no other profession that has done anything like it. Imagine economists at the Federal Reserve holding community meetings to decide the direction of fiscal policy. Imagine public health officials giving equal weight to the nutritional wisdom of teenagers — they are stakeholders, after all! Granted, powering up the grassroots was necessary in the 1970s to stop expressway and renewal schemes that had run amok. But it was power that could not easily be switched off. Tools and processes introduced to ensure popular participation ended up reducing the planner’s role to that of umpire or schoolyard monitor. Instead of setting the terms of debate or charting a course of action, planners now seemed content to be facilitators — 'mere absorbers of public opinion,' as Alex Krieger put it, 'waiting for consensus to build.' 
The fatal flaw of such populism is that no single group of citizens — mainstream or marginalized, affluent or impoverished — can be trusted to have the best interests of society or the environment in mind when they evaluate a proposal. The literature on grassroots planning tends to assume a citizenry of Gandhian humanists. In fact, most people are not motivated by altruism but by self-interest. Preservation and enhancement of that self-interest — which usually orbits about the axes of rising crime rates and falling property values — are the real drivers of community activism. This is why it's a fool’s errand to rely upon citizens to guide the planning process. Forget for a moment that most folks lack the knowledge to make intelligent decisions about the future of our cities. Most people are simply too busy, too apathetic, or too focused on their jobs or kids to be moved to action over issues unless those issues are at their doorstep. And once an issue is at the doorstep, fear sets in and reason flies out the window. So the very citizens least able to make objective decisions end up dominating the process, often wielding near-veto power over proposals.
Late in life, even Jane Jacobs grew frustrated with the timidity of planners — Canadian planners this time. In an April 1993 speech — published in the Ontario Planning Journal — she lamented the absence of just the sort of robust plannerly interventionism that she once condemned. Jacobs read through a list of exemplary planning initiatives — the Toronto Main Street effort; the new Planning for Ontario guidelines; efforts to plan the Toronto waterfront; and plans for infill housing, the renewal and extension of streetcar transit, the redevelopment of the St. Lawrence neighborhood, and on and on. And then she unleashed this bitter missile: "Not one of these forward looking and important policies and ideas — not ONE — was the intellectual product of an official planning department, whether in Toronto, Metro, or the province." Indeed, she drove on, "our official planning departments seem to be brain-dead in the sense that we cannot depend on them in any way, shape, or form for providing intellectual leadership in addressing urgent problems involving the physical future of the city." This, I hardly need to add, from a person who did more than any other to quash plannerly agency to shape the physical city. 
The net is the planners have no vision, and no one else does either. The question then arises, is vision necessary, or even good? Those who believe in the merits of the decentralized world would argue that vision, especially big visions, is more likely to do harm than good.
I would argue we need some form of vision, on which to base current decisions. But we need to continually re-evaluate those decisions, and that vision. We cannot get stuck on zombie plans, which is what visions often lead to, but we also cannot act aimlessly.