This document provides a summary and critique of a proposal to build models for a sustainable Germany by 2040. It notes that the proposal makes some good points but its economic understanding is still simplistic and it is insufficient in design and scope. The summary recommends using systems analysis throughout, integrated assessment modeling to analyze past data and scenarios, and involving experienced systems analysts. It concludes that the proposal has some blind spots and needs to better connect the whole system, address issues like population and trade, and engage policy/government to enable real paradigm shifts.