I've promoted the rebuild at Kennedy for years but no takers. Without a highway how do you expect it to be a city centre.Temporarily. Metrolinx has since discovered they can build out the GO line without removing the RT stations; which means you could still use the RT space for another use in the future.
Eglinton LRT is in the way now though as it's at the same depth as the subway. It would likely be much easier to extend Eglinton LRT into the corridor and replace part of the Eglinton East extension with the subway.
Might be cheaper to demolish SCC (station, mall, city offices, and condos) and rebuild the entire neighbourhood at Kennedy.