Why Toowong? The existing express pattern is express Milton to Darra, stopping at Indooroopilly. I think it’s best not to have multiple express patterns—they’re inefficient, and confusing.
Go have a look at the NSW CCN timetable someday if you want to see a real shemozzle.
I don’t think it would require much—Eagle Junction to Clayfield, a second platform at Hendra, and re-open P2 at Doomben.