1. I think its strange to say that King cant be disrupted because it has a heavy streetcar route. Seems like a good reason to put a subway under there. It will need to be bored downtown, because it needs to be deep enough to get under the YUS line. Its worth a few years of disruption for decades of having a subway under the street. (See Yonge, Bloor, etc.)
2. the southern end of the financial district around Union is already extremely well served. And as I said earlier I dont buy the need for transfers from DRL to Union. The financial district also isn't the only ridership draw in the area.
3. Why would you need a sharp dip down to the rail corridor in the west? Why can't it just stay on King. It could be a simple straight line. If the goal is to serve the exhibition, King still does pretty well. I used to live in the area, and there are always TFC crowds walking to King to catch the streetcar, and the whole area is packed during the Ex. Afterall, its in the summer, and if people cant walk from King to the Exhibition grounds, then they probably wouldn't go the the ex in the first place.
4. I agree that a King alignment almost definitely precludes a Queen Subway in the future. But I dont believe in sacrificing the alignment for this line on the off chance we will get a second downtown line in the next century.
1. The DRL would intercept a large part of the King ridership regardless of whether it's on Front, Wellington, or King. So why would you allow excess disruption when it's almost entirely unnecessary?
2. You might be saying the Financial District is well served now (actually, I wouldn't,) but what will that be like if the TTC's ridership even increases by a meager 20 or 30%? Just having 2 or 3 stations in the financial district (all on the same subway line,) will show a real bottleneck in the system in the future. The connection with Union is important to better connect the entire South of Bloor/Danforth district with the station, which in turn connects those areas with the rest of the city and even other cities when rail gets improved. Also, if the Financial District is already "well served," what other place in downtown is not well served that would need another subway line more? The Financial District has a very, very slight edge on routes like Queen or Dundas in terms of subway coverage (3 stations instead of 2,) but has a much, much higher need.
3. Cost savings. Using the rail corridor would save a bundle, and serves CityPlace, the CN Tower and Skydome, and hits the Ex straight on. I can tell you, coming from a hardcore TFC fan, I would be quite disinclined to go to the Ex from King. I once went to a Marlies game from a restaurant in Liberty Village (already well past King,) and it took quite a long time. If you want people to have transit integrated into their lives, a station at Exhibition loop to get people going to the Ex, Marlies, Ontario Place and TFC (and whatever else they cram into that area in the future,) is a good way to start.
From there, I personally would start heading back up to King, stopping at Liberty and Dufferin, Parkdale and Roncesvales. But wherever you want to go a rail alignment is important, at least until the Ex.
4. Obviously not, it was a little point. But remember that with a southern alignment DRL, an Eglinton-style Queen LRT should still very much be in the books.