Engineering has never been a linear profession. We are subject to constant change - - where recently change has been exponential in nature. The elements of change that most impacts engineering comes from many different avenues. These include economic crises, political shifts, new technologies, new discoveries, and new market shifts. In 2011, we say huge changes and "trend-busters" in all five areas. The challenge for engineering, given rapid change and uncertainty, is knowing what to build, at what time (engineers from Apple to Fluor face this same challenge - - it is universal to engineering).
We cannot know what will happen in the the future (remember the old Russian saying - - "Those who try and predict the future never get rich") - - yet we seem fixed on a mindset of "design to specification" or "design to present requirement." Many of our current methods do not deal effectively with the notion of rapid and complex change. Engineers could greatly improve results by recognizing that the future is inevitably uncertain and that by creating flexible designs that can adapt to eventualities. Considerable value can be derived from engineering focused on "designing for variation."
Designing based on "Master Plans" will seem rigid and deterministic in a era of flexible designs. The reality of rapid change needs an environment of "intelligent management" - - flexible design anticipates and plans for a range of possible futures. Flexible designing will enable system owners and managers the opportunity to respond easily and cost-effectively to changing circumstances.
Richard de Neufville and Stefan Scholtes have an excellent book on the subject - - Flexibility in Engineering Design (2011).