IMO, bad idea. They will always get stuck in mixed traffic. That section of Bathurst is too narrow for a dedicated ROW.
Bathurst LRT is possible, but it would start at Wilson subway station, go to Bathurst, and then continue north. That section has room for ROW.
For now, how about the Bathurst streetcar going into St. Clair West station first? It would require very few new tracks, as most of the infrastructure is already built.
They'll need to put carbarns adjacent to the Wilson yards.
I think the demand along Bathurst is split fairly well at Bloor, so it may make sense to keep the route split there, and bringing the streetcar up to St Clair West could disrupt the St Clair route.
Extending the Bathurst streetcar north of St. Clair Avenue West should have been done in the 1950's, when the Toronto Transportation Commission was expanded and became the Toronto Transit Commission. However, "riding on rubber" (buses) was the "way of the future" in the 1950's. Many other routes should have been streetcars, as well, starting in the 1950's, but are too late now. Transit City was a start, and only a start, which the current city hall administration is trying to derail.