The fact is, Metrolinx bungled the handling of the Brentcliffe-Don Mills alignment. From the minute the 2010 EA came out with the median arrangement, many of us pleaded for a south-side alignment so it would be grade-separated through to Don Mills and so also the Leslie intersection would remain functional for cars. Metrolinx said they'd study it and the result was the proposal to tunnel all the way to Don Mills. This was overkill and predictably the STIMBY's (Stop in my back yard) from the Leslie condos (aided inexplicably by the Leaside Property Owners Ass.) put pressure on local MPP Wynne (who was running to be Premier) to revive the Leslie stop. By the time this process played out, most of a year was wasted and then the order was "lets get building" so they never revisited a south-side
surface alignment; they just reverted to the EA.
Metrolinx claims that it's difficult if not impossible to emerge from Brentcliffe portal on the south-side. Just like a year ago they claimed it was impossible due to slope issues and soil contamination to launch at Brentcliffe at all. Hogwash!
I think another reason they are stubbornly refusing to look at the south-side alignment is that they are desperate to save every penny possible to cover massive over-runs elsewhere. Look at the plans for Eglinton-Yonge station. While I welcome them as a definite improvement over the last proposal, they won't be cheap. Extending the Eglinton subway platform (on the Yonge line) 70m north so that the station will extend directly overtop of the Crosstown platform and thus allow a direct connection! This extension will require closure of Yonge subway service from time to time and will unfortunately result in the elimination of the pocket storage track north of Eglinton.
Still in the long run this is a good solution and will be worth it!
Unfortunately the same logic isn't being applied at Leslie. That one intersection will be the weak link in an otherwise strong chain from Mt. Dennis to Don Mills. There are many possibilities for Leslie to be grade separated without incurring the huge cost of a tunnel extension but I don't believe it will even be looked at.
At least when the traffic is backed up to west of Laird waiting to turn north at Leslie and when LRT's are delayed at Leslie waiting for their turn in the 3 cycle traffic lights, the trains will be smoothly running to Laird. Even if stuffed trains from Don Mills (due to increased headway east of Laird) arrive at Laird, the good people of Leaside will enjoy the fact that every second train will be empty having been short-turned at Laird.
I think the LRT (after getting through the construction nightmare) will be ok from Mt. Dennis to Laird. If east of there even gets built (and I don't think it's a sure thing), it will be traffic and LRT chaos to say the least. Then again by the time the at-grade contract gets awarded we could see various govts. change and this whole exercise will have been academic!