What I think is a missed opportunity here is tying in Malton GO station. Furthermore, I would like to see how a discussion between Metrolinx, the GTAA and the CBSA would go about making the airport area such a major transfer hub.
To me, it would make much more sense to have both of these lines terminate at Malton GO, allowing for GO passengers to transfer to them. Also, and more importantly, instead of having to build new rights-of-way between Kitchener-Waterloo and the airport, you could just detrain at Malton, hop on the Crosstown, and get directly into terminal 1.
If you consider the costs for Finch and Eglinton LRTs to be set (already identified in the Big Move, and funding being allocated through dedicated revenue tools), what would the cost difference be between making necessary upgrades to the existing rail corridor from KW to Malton (also already slated to be electrified for GO service), reconfiguing the Eglinton+Finch LRTs, and making Malton a mobility hub instead of the airport?