With the mid-block stops eliminated of course, and preferrably in an elevated and/or trenched guideway.
I'd even be OK with surface LRT if the stop spacing is wide enough. For suburban arterial LRT, 1km spacing is more than appropriate, 500m is overkill.
Now, what should the Eglinton LRT be extended from the airport to Renforth Gateway?
Since they'll be the same gauge (yes, the Flexity Swifts being delivered are standard gauge vehicles), my preference is to extend the UPX spur South to connect with it and run Eglinton LRVs on it all the way to the Kitchener Line to intersect with a High Speed Rail station around Highway 427.
Now, how low-floor LRVs are supposed to work with a high-level platform at Pearson without significant reconstruction? With the current Terminal 1 station layout, is a southern extension of UPX viaduct even physically possible, let alone financially reasonable? I have no idea. This could just be throwing more money at a sunk cost fallacy.
I guess having LRT extended to the airport would't be that bad of an option, but it might not be necessary given that most people coming from Toronto will be on RER and most people coming from Mississauga will already be on a bus. Maybe just have a free transfer at Renforth to a shuttle bus? Extend the LINK train? Convert the LINK to LRT?
(might be good to copy this discussion to the Eglinton Crosstown Thread)
...
Back on topic; low-floor or high-floor EMU vehicles for GO RER/SmartTrack? I like the idea of switching to high-floors, but GO's entire system is low-floor and would require some conversion. High-floors are better for tunnels, but are there even going to be that many station tunnels to begin with?