First off, great work from all the F24+ teams in getting off the line at Goodwood, I was really expecting to see one or two cars not making it away.
There was however a large speed differential between the cars as they came off the line. Its pretty much a given that Dave is going to be in the lead by the end of the first lap, but the car was swamped off the line, causing a significant opportunity for a crash.
Having the cars line up on the grid in order of 'start effectiveness' would reduce the speed differential between cars during the period at the start of the race when there is the greatest opportunity for a crash. Jet & RR still have to perform the same number of overtakes as if they'd started at the front of the grid and started slowly, whilst avoiding the risk of being rammed from behind by faster starting, but likely less experienced drivers.
Basically, this grid method would reduce the net number of overtakes during the period where a crash is most likely.