Just curious- what do you envision for a different format? What do you see wrong with the current format?
Also, unless things get electrified relatively soon, wouldn't a Park Lawn station be a bit close to Mimico? Trains stopped at one would barely start chugging along before they have to stop at the next one.
I hesitate a bit to answer since my response would not necessarily be the same as that of drum118 who offered the original statement about the format of GO stations such as Mimico. Moreover, my own response might be overly influenced by the two GO stations I know best, Mimico and, from a former spell in Toronto, Guildwood.
Most of the GO stations I have seen are in low density suburban areas, surrounded largely in the early days at least by single family homes, with provision for large amounts of parking. I have no criticism of the original choice to build that way. That was what was "there" on the GO routes when the system was inaugurated. As far as I can tell, these were intended to be "drive up" facilities. Suburbanites, of whom I was one, were expected either to drive to the station, park in the large lots, and take the train downtown, or be dropped off from the family car at the "Kiss and Ride" circle. But not all GO stations need to be built or should be built on that format any more.
Toronto now features nodes of high rise density in many places in the former suburbs. Of these the towers along the Humber Bay Shores are only the tallest and most visible. This node is also directly across the street from the railway tracks, offering the possibility of constructing a new station in easy walking distance from a large population. That potential walk up ridership is far greater than at the present Mimico station. The area also offers the possibility of creating a purpose built transportation loop to link other forms of transit to the GO system. The present Mimico Station is served by one suburban TTC bus route, sort of, not very well, to be honest. It would be a difficult task to improve this at Mimico station, I think.
In my mind and I think several other posters here, the format change you were asking about is from a drive up format to a walk up format and a dependence on transit accessibility rather extensive parking. In these respects a potential Park Lawn/Humber Bay station would be greatly superior to the rather cramped, inaccessible and generally off the transit grid Mimico station.
The question about the short distance to the present Mimico station has been addressed in several places on this board. One possibility would be to bite the bullet, face reality and close the GO station at Mimico. (Developing the property might pay for the cost of a new facility. Another developer would probably be able to avoid the disaster represented by the development which is the subject of this thread,) But closing a facility is always a political hot potato and I can see that might be difficult. The other possibility is to alternate services to Mimico and Humber Bay Shores. But in the end we collectively need to be realistic here. Humber Bay Shores is where the people live and it is potentially accessible by transit to a wider population than the present Mimico Station. It is also where the voters live and where many more of them will live in the very near future. This is a fact of political life that the local councillor and other political leaders would be wise to remember.