Where this comparison fails for me is that over vs under engineered is not the only dimension that is a factor in maintainability. I have experienced very poor

Where this comparison fails for me is that over vs under engineered is not the only dimension that is a factor in maintainability. I have experienced very poorly engineered code (from a best practices standpoint) which easily would be considered over engineered, and very well engineered code (again from a best practices standpoint) which falls squarely in the under engineered bucket. In my experience, the code that most closely follows best practices, be it either over or under engineered, will be easier to correct.