Not enough is correct, however it often gets brought up because it has such enormous potential to give riders maximum interchange connectivity. There are several goals it would accomplish by having an interchange somewhere on the Bloor line. It would relieve developing capacity issues on line 2, it would relieve overcrowded north south bus routes and provide rapid transit connectivity to busy areas of the city that are underserved.
Interchange from where to where? Line 2 to Liberty Village / CNE take Line C (Kitchener), Line 2 to Airport or Downtown take UP, going to north downtown stay on Line 2 to St George or Yonge, going into the neighbourhood transfer onto the bus or streetcar. What is the gap that an Ontario Line to Dundas West is expected to fill?
It would also make a lot of sense with the eastern part of the line in terms of the types of trips people will be taking and provide redundancy to an overstressed network.
The frequent service from Dundas West to downtown will be new... how can it be overstressed on day one? Where is the network stress that is being relieved?
Furthermore, the density along Dufferin is greater (and will be in the future as well) than anywhere in Etobicoke and has less transit available. There are other neighbourhoods in the west in a similar situation. I say this all as someone who used to ride the 191 every day.
The 191 doesn't stop at all the developments along the way or the Renforth airport corporate centre. Have you been on the TTC 111 and 112, plus the Mississauga 35, 107, and 109 which all currently take people from Kipling to Eglinton and 427 area? How does an Ontario Line to Dundas West improve the bus capacity challenge on Dufferin better than non-stop Dundas West to Liberty Village service?
You point out rightly that people will want to go from the airport to northern destinations without travelling south first, but there is no advantage to making that route part of the Ontario Line. It would make more sense to continue a northern 407 alignment all the way to Oshawa GO and maximize transfer points with all north south lines.
This loop is the provincial plan. I'm more interested in the "U" of the Ontario Line than the "O" which includes the connection across the top which will not need Ontario Line capacity for a while. I agree that at the airport or at 407 a transfer to a Oakville-Oshawa 403-407 connection of some sort likely makes more sense in the shorter term. However, if the density proposed at 7 & Weston, VMC, Richmond Hill Centre (south of Bridge and High Tech), Beaver Creek, and Markham Centre all materialize that is going to be a dense corridor that is ill served by asking people to walk from Highway 7 to the freeway (almost a 1km walk from most buildings) and I can see at some point VIVA will not serve that capacity well... but again... not a high priority in the short term because VIVA reaching capacity is a ways off now.
I don't see any advantage to having the OL try to be everything all at once. I also cant wrap my head around tunnelling under vast amounts of SFH when low cost right of ways exist.
If you are in Humber Bay Shores and want to go somewhere other than a location other than downtown or Lakeshore West, what option is there? If you are arguing the point that the Ontario Line should end at Exhibition, then I can understand that perspective... it is the perspective that north-south capacity is adequately served.
If you are arguing the point that somehow having the Ontario Line go Dundas West makes sense, then I don't understand that at all because that line already exists (Line C for express, and 504 for a more local option), and to get to Dundas West from Exhibition you would likely pass under SFH to serve places already served.
Why would someone look at this map and say "that blue line should really follow almost exactly the red ones".