Better than that...here's what they should do:
1) Subway to STC. Even at $320M/KM. That's $1920M.
2) Use the remaining $780 million to build LRT along McCowan from STC into Markham and a spur along the corridor from Sheppard/Progress to MTC. This would allow for a Don Mills-Malvern service, a Malvern-STC via McCowan service and improved service on McCowan itself, which is already a very busy corridor.
3) Bus hub at MTC. Or just extend the LRT further north, up Neilson to terminate at Morningside Heights.
That's all providing they keep the SELRT.
What's a waste is spending a ton of money to build grade-separated LRT east of McCowan when it's just not needed by any measure, wasting money there, while STC is seeing remarkable residential and commercial growth that's pushing it closer and closer into subway territory.