One of the plans was to actually extend the Scarborough RT not only to Malvern, but with a fork going west along Sheppard to Downsview.
IMO that would have been a good plan. It not only would have been more suited for the ridership, but it would have turned the RT into a suburban line with merit beyond a stubway to nowhere. It would have given purpose to the transfer at Kennedy.
The RT could then have been extended northwest along Finch, and possibly to the airport south, connecting to the then planned Etobicoke RT, creating a suburban belt line of sorts, similar to the GO ALRT plan.