It seems like it is a good idea because it is.
And cheap too, I don't recall the exact figure but I remember someone saying it would only cost in the ball park of 800-900million. (If someone does know, I'd like a more accurate number) Well short of the several billion-dollar lines that are usually talked about back and forth on here and at city council. Its probably the line that can benefit the most, for the cheapest, and be constructed the quickest.
The WWLRT has many flaws and needs to follow the idea of having the line on the Lake Shore 100% west of Bathurst Street. A new bridge over the Humber will have to be built to keep the line on Lake Shore 100% and bypassing the Humber Loop.
The plan TTC had to take the line through CNE to Dufferin was so so, but fail to service the waterfront and Ontario Place.
Taking the line north over the rail corridor and running it along the side of it to the Queensway is pure dumb as well removing track capacity for GO to not to have the 6 tracks in this corridor.
When the EA was done a few years ago about rebuilding the Lake Shore, TTC plan was scrap for the north side and was put on the Lake Shore.
Taking the line east of the CNE along Fort York and Bremmer to connect to Union Loop had all kinds of issues that TTC refused to look at. Even Concord for the City Place Development saw no need a line here to the point they were force to build the new Fort York Rd with room for this line in the middle. This line had an impact on Old Fort York itself and with the new visitors building being built has kill that idea.
When ACC was built, a new tunnel and ramp was built under it to connect to the Bay Tunnel and surface at the west side of it in the circle turn around. This would cause an operation issues for the current 509 & 510 cars heading in/out of the loop with is new line crossing it. At the same time, TTC was looking at running a 514 off Bathurst route to Union.
When the EA got underway for the new east Queens Quay line, this flaw show up real nicely that the new expansion for the loop would have lack of capacity for it as well causing a nightmare for operation.
The new loop would only handle 10,000pph for all lines and the expectation was to be 15,000pph with 60 seconds between cars.
The cost of that expansion of the loop has kill the building of the east QQ line to the tune of $375m.
At the same time, the residents of Mimicoe don't want a ROW considering traffic doesn't play a real problem for operation today there today.
There is a way to fix the Union Loop mess, but the city and TTC refused to look at or think about it.