2 Problems:
1: There is no reason we shouldn't be future proofing this. Sure, the 407 Transitway won't be built tomorrow, but there is no reason why we should put ourselves in a position where we'd have to relocate the station 20-30 years from now, especially since some form of Rapid Transit along the 407 is supported by every major party. The 407 Transitway/Rail isn't some project that only exists in the imagination of some foamers, its a project that has had its EA completed, and is listed as a long term priority by both parties. There is no reason why we shouldn't factor it into the design.
2: Even if there is no 407 Transitway, we still have a ton of regional busses travelling along the 407, which forms a major backbone in circumferential travel within the region. If you're travelling from any major urban area to another area that isn't Toronto, odds are you're travelling along the 407 corridor. I mean, christ, the corridor has extra bolding applied to it on the GO Transit Map for a reason
View attachment 476135
So, instead of having a nice and convenient transfer that could be done by building a small platform on the side of the highway similar to what you'd find in Vancouver, now any bus that wants to serve the station has to waste 10 minutes getting off the highway, and maneuvering through local streets just to reach the station. With this increase in travel time, the business case has also revealed that the plan is to only have
2/6 407 SERVICES STOP AT CONCORD. THAT IS INSANE, there is no reason why Concord GO should have lower connectivity than HIGHWAY 407 STATION, and this wouldn't even be a problem if we have a properly designed interchange than wasn't a headache for all of the GO Busses serving the corridor.
P.S. Are you really telling me that interfacing with Viva Orange is a higher priority than regional GO busses? The ibc outright states that the main benefit of the station existing is to interface with 407 GO Busses so its clear the intention is for it to be a regional hub.
Sorry for the blurry image.