I will contend that conceptual integrity is *the* most important consideration in system design.

Related:

• Conceptual integrity in turn dictates that the design must proceed from one mind,
  or from a very small number of agreeing resonant minds...
• The flow chart is a most thoroughly oversold piece of program documentation.
  Frederick P. Brooks, Jr., The Mythical Man...
• Plan to throw one away. You will anyway. -- Frederick P.
  Brooks, Jr., "The Mythical Man...
• The flow chart is a most thoroughly oversold piece of program documentation.
  Frederick Brooks, Jr., The Mythical Man...
• The management question, therefore, is not WHETHER to build a pilot system and throw it away.
  You WILL do that. The question is whether to plan in...
• How does a project get to be a year late? ... One day at a time.
  Frederick Brooks, Jr., The Mythical Man...
• The hypothesis: Amid a wash of paper, a small number of documents become the critical pivots around which every project's management revolves.
  These are the manager's chief personal tools. -- Frederick...