Wonder if possible for a tunneled section to veer north after Senlac and realign with Finch at Bathurst, to maximize the area served? There seems to be a few clusters of density and redevelopment opportunities along that route.
AoD
Interesting idea, there's a bunch of different possible combinations. That would mean a significantly longer tunnel though. Unless of course you did surface up Bathurst, but even then it would be more expensive than tunnelling to Downsview and then doing cheap LRT in an open space and along a rail corridor.