Well I can tell you exactly what went on at Williams. Although Bobbo is largely correct the change to the Renault engine was/is a massive influence on the upturn in performance. Getting rid of Sam Michael was definitely another major factor and the others were the hiring of Mike Coughlan, Mark Gillan and also Jason Summerville as head of Aero in place of Jon Tomlinson. Everything started to work properly after those changes. Their Achillies heel now is their drivers.
Agree - but don't forget Ed Wood & Dickie