Both theology and engineering are systematic endeavors. In engineering systematics is unavoidable. Systematics means completeness, coherency, and compliance with all available knowledge. The reason engineering must be systematic is because if it is not bridges fall down, airplanes crash, and people die. As a result engineering must correspond to the reality of things. This means that it is not enough that certain parts of an engineering design seem to fit the reality of things but that everything must work. The same should be true for theology.
Now engineering is a field that works with a very limited subset of reality. It deals with macroscopic entities that, as such, can be very regular and predictable. Theology has no such definiteness. However, theology should still aspire to the same systematic rigor and pragmatism of engineering. It can do that if it adopts the same requirement that partial solutions are not acceptable. When a theology seems to solve certain problems but comfortably avoids the hard spots, it should be rejected out of hand. We see this all the time.
Theology claims to represent the ultimate reality of things. If it is to do so it must first claim that the ultimate reality of the cosmos is knowable. In order to do that it must affirm the profound religious intuitions that have persisted for millennia. It must do that but not uncritically. As we all know intuitions can be mistaken. If there is an ultimate reality to things then religious pluralism speaks loudly that religious intuitions concerning that reality cannot all be totally true. With this problem the question arises how to adjudicate these differences. In engineering pragmatism rules. This should also be the case for theology. It must work in a complete systematic way. This means that adjudication occurs within a constant dialog between theological concepts and ultimate reality as it is experienced. This is the same criterion that is used in physical theory. While I suggest that physical theory will never be able to reduce the emergence of reality to a set of equations, it, none the less, does not accept anything that is not complete. The same should be true for theology.
What we find in many current theological systems that rightly try to find a consilience with reality and theology is that certain aspects of religious concept and practice are problematic. If one is to look for problematic areas the issues of divine personal action and the efficacy of prayer come to the forefront. The intuitions of millennia attest that these are cardinal issues for theism. For systems that do not accommodate continuous divine providence and personal relation to the divine, one should be rightly skeptical.
Any theological system that aspires to be relevant must find a way to honor these millennial intuitions. It must work in the reality of core religious sentiment.