Elevated is still far too much infrastructure for this location. At grade is all that would be needed in this industrial wasteland.
I took a look at the bus route it would replace, and it seems to be one that runs every 20 minutes. Needless to say, a train running at my theoretical 10 minute frequencies would appear to be a little overkill.
But, given the price tag of an at-grade extension could be relatively low, it might be something that Vaughan would be interested in, as an investment in (a) connecting employment lands in Concord to downtown Toronto, (b) increasing development value of VMC, (c) increased tourism to Wonderland/Vaughan Mills