Let me start by answering this question straightaway: it depends. The floor plan of an office needs to reflect the organizational culture and management style of that office. As with many of my prior articles, “business know thyself”!
At one end, is the culture typified by a stable business model and mature market. The company itself has been around with improvements, but no radical change for many years, possibly decades. It probably has developed an office migration strategy as part of its informal compensation plan where privacy has value based on old military models. At the bottom are the soldiers: well trained to do their job and they are typically in an open configuration with little privacy. Everyone can overhear their conversations and walk around seeing what is on their screens. This is a command and control environment. Supervisors and low-level managers get a tiny but more privacy, perhaps with a glass walled office, to reflect the need to do a private conversation with employees, but strategic direction and client relationships are not really part of the job. Their task is to ensure the troops follow the battle plan laid out by the generals. Upper management gets to have the ego stroking separate floor and conference rooms so they can do bigger thinking and bigger conversations with clients who need to feel special. There really is nothing wrong with this model, and many people thrive in it. It may stifle innovation, but in a mature business that is not really as important as following the process with perfection.
At the other end of the spectrum, and most organizations are not at either end of this pendulum, is the type of company described by Richard Sheridan in “Joy Inc.”. This advertises an open room with no fixed interior walls where everyone sits and that includes the CEO and HR/Payroll. There is no privacy at all for anyone, but somehow the group mentally motivates and encourages everyone such that production is high, and innovation is constant. This business model is one of constant new projects where the communication pace of the standard hierarchy would be too slow and inefficient.
As stated above, most companies are in-between the extremes, but careful self-reflection on company culture will reveal how much togetherness makes sense for your situation.