It's impressive, like all of the other stations on the extension, but the final concept demonstrates that politicians and designers really drove this project.
New subway stations are going to be larger than their 1950s and 1960s predecessors due to changes to the building code. We should also expect a pleasant design, rather than the bare basics that were often, but not always, constructed in the past.
This station is over-designed though. I understand that the YRT and GO Transit believe that eighteen bus bays will be required, but the boomerang-shaped platform appears to be less efficient than an island-shaped platform. A large platform is required regardless but, looking at the diagram, many bus routes will travel longer distances to and from "the gate" than if an island had been chosen. This will waste time and waste gasoline.
I agree with previous comments that, for all of the talk about intensifying development around existing stations and building it into new stations, Highway 407 is a missed opportunity. Will the area ever be urban like downtown Toronto? Probably not, but this design will hinder rather than help the area along that path. Station entrances really shouldn't be so far away from the street. Even if there isn't anyone to walk up to the front door from the sidewalk at present, it doesn't mean that there won't be in the future.
The boomerang shape isn't all that friendly to commuters either. The "wings" help to push some of the parking out further than it would have been otherwise, which increases walking time to the main entrance. Unfortunately, deep stations come with tunnel boring, but we shouldn't be compounding the vertical commute time with long walks from parking lots and with potentially long walks across bus platforms. Never mind that, for such a large facility, there is only one public washroom!