The station that bothers me the most is Sheppard West/Downsview Park. The entrance is massive and it doesn't look like it will support any development near it. It seems to be designed under the assumption that it will always be in a park. But if that's the case, what's the point of even having a stop there? The industries on the north side won't make much use of it, and Downsview Park isn't really that large of a trip generator.
I think it's primarily because of the transfer between TTC and GO. But yes, I agree that it's larger than what's needed.