> Components like exterior walls and roofs were designed to have as simple shapes as possible (no complex hips or wall jogs), and

This is a traditional and eminently sensible approach that has been lost in the "McMansion" era.

Simpler roof shapes are not only cheaper to build, but also are far easier to deal and insulate, and therefore more energy efficient.

Instead, simple energy efficient design is today mostly used in some high end custom homes while production homes are often overly complex and inefficient, relying on oversized mechanical equipment to make up for poor design choices.

> rooms were arranged so that plumbing lines could be placed near each other to simplify pipe routing.

There's a simple method to quantify this known as the "hot water rectangle". On the house's overhead view, draw the smallest rectangle that includes all the hot water faucets and the water heater.

The size of the rectangle affects build cost, efficiency, and hot water delivery performance. In many large houses there is no consideration for this at the design stage, so they end up using (wasteful) hot water recirculation pumps.

1. https://www.greenbuildingadvisor.com/article/the-hot-water-r...