It would have been pretty hard, considering where the tracks currently go (from Bloor, they swing down towards the lake, to Queen and Dufferin, then parallel to the lake until they get to Union). The closest stop to Spadina would be the Union stop, the only way to make it closer, given where the tracks run, would be to add a stop outside the Rogers Centre, which would not be practical. I actually think the Bloor stop's proximity to Dundas West is about as close as one could get, given existing infrastructure - it isn't a bad option, and better than many options I have come across in other parts of the world.

I may well use the service, at $19 (Presto fare) it is considerably cheaper than a cab, and it almost certainly quicker than taking a cab. I do work on Bay, so it is convenient for me if coming from work (not from home). The statement "but very few people will not have a lengthy commute to get to Union" simply isn't the case, tens of thousands of people work within an easy walk of Union station, and I think that is who it is aimed at, not people from the north or east end of the city, anymore than the bus that went from downtown was designed for them. A huge number of tourists will be within an easy reach of union (just thinking on the number of hotels close by) so it is good for them too (when you get large families, not so much compared with a minivan taxi, but there are still a good number who would prefer the certainty of a train (time and price) than a cab (plenty of cities rip off tourists, although I haven't experienced that issue in TO myself). )