I'll play Devil's Advocate (I also think reaper is being a little misleading as you allude to by citing C-train and ETS, both of which use old rail lines for very discrete right-of-ways that Toronto doesn't have) and say that the remedy to TTC's streetcar problems have been known about forever, Toronto just doesn't want to nut up and fix them: much wider stop spacing so trams can get up to speed, stronger signal priority, institutional pushback against train-delaying customer service decisions (slow door closing drama), and modern switches that don't require crawling through an intersection. Toronto should do this at the bare minimum before we start worrying more about grade separation.
If I was Olivia Chow, I would simply order the TTC to close half of King St's tram stops tomorrow. People will whine and complain about accessibility, as if a streetcar requiring you to dart across a lane of active traffic is some kind of wheelchair utopia, and the city will adapt. It's crazy that the city is desperately trying all kinds of schemes to speed up King St and ignoring the elephants in the room.