What is the name of the architectural principle that is designed to be as straightforward as possible but still meeting enterprise requirements?

The principle of Simplicity dictates that architectures and solutions should be as straightforward and uncomplicated as possible, while still fulfilling all necessary enterprise requirements. This principle aims to reduce complexity, which can lead to lower costs for development and maintenance, easier management, and a reduced risk of errors. It avoids "gold plating" or adding features and complexity that are not required to meet the defined business needs. The goal is not simplicity for its own sake, but rather the simplest possible solution that is effective and fit for purpose.

A. Reuse focuses on leveraging existing assets and components to increase efficiency, not necessarily on being straightforward.
B. Agility focuses on the ability of the architecture to adapt quickly and cost-effectively to changing business needs.
D. Openness focuses on using non-proprietary standards to enhance interoperability and avoid vendor lock-in.

ISACA, COBIT 5: A Business Framework for the Governance and Management of Enterprise IT, 2012, Page 41, Section "Principles, Policies and Frameworks Enabler". It states principles should be "expressed in simple language," supporting the concept of simplicity.

ISACA, COBIT 5 for Information Security, 2012, Page 51, Table 10, "Information Security Architecture Principles". It lists "Simplicity—Ease of use, implementation and administration of security measures."

ISACA, COBIT 5: Enabling Processes, 2012, Page 90, Process BAI03. This process requires that solutions align with enterprise architecture principles, of which simplicity is a common and fundamental example.