Well having to totally rewrite it, will require all embedded assumptions to be identified and re-evaluated, including the forgotten ones.
>CO2 is NOT the control knob on the climate
Maybe, however the knowledge about the role of CO2 has arisen in recent years and could be taken to be unknown in the 1970's when the models were first constructed.
So you and other climate septics should be pleased about this project and lobby to ensure it gets all the funding it needs so that it can be completed and be useful...