East end indeed... there are only tiny bumps in the west end. This list needs more Beaches climbs (where do I begin?!), Beechwood, and MeadowCliffe. But Kingston Rd? What kinda glue is the author smoking? :)
Maybe begin at Gate's Gully? - not for those of us with only road bikes - but that is one impressive average grade for a 1km climb...
I'm been playing around with linking up some of the shorter Beach climbs into circuits and there's a lot of fun to be had there. I love Pine Crescent with the cobbles (and if you add Balsam unto it you get ~1km @ ~4%), throw in Beech and a few of the other shorter ones and you've got yourself a great workout with a bit of variety right in our backyard.
Agree that Kingston Rd between Woodbine & Victoria Park is a strange choice. The grade is modest and the traffic is best avoided.
Gates Gully is definitely the hardest hill in Toronto. No contest whatsoever! It is currently closed for TRCA maintenance on the ravine creek. The work on the creek is finished and they're currently repairing the trail a bit. For now it, will be fresh limestone screenings which will definitely make it possible to ride on slicks (albeit 28c recommended). This is projected to be finished by mid-May. Looking forward to checking it out soon! :)