I think I've reiterated my point ad nauseam that GO and subway serve different markets, and therefore both are required. Even with regional rail, I think a subway would still be required. The subway should stay on Bloor St and not divert to Dundas anyway. So if that were the case, they really wouldn't be that close to each other anyway.
Of course GO and subway serve different markets. GO is a commuter service. You've got to understand that regional rail is absolutely nothing like GO.
Nothing like GO. Regional rail is rapid transit, just like subway. GO is commuter rail service.
Besides, your point about having rapid transit close to each other is pretty moot since if MCC got regional rail, every other GO line would have it as well, and there are many "parallel" GO and TTC subway lines. So that's not a limiting factor.
When you talk about parallel future regional rail corridors and subway lines, you're right to an extent. There are two important differences, however. The existing parallel routes are actually quite distant--definitely not within walking distance like the Mississauga rail corridor and a Dundas subway. The other rail corridors have relatively infrequent stops compared to the parallel subway. As far as I can tell, any subway extension to MCC would more-or-less replicate the stopping pattern of a regional rail route.
I also don't see how spending billions to divert Milton to MCC is going to really be any better than spending billions to extend the subway to MCC. I see this whole regional rail thing as something taking place far in the future, because as it stands, we're nowhere near it now. A train every hour (as on Lakeshore) does NOT provide subway-like frequency. And that's the closest thing we have as now.
I just don't understand how you can't see that a regional rail service that provides a faster, more comfortable ride and serves all of Mississauga instead of just a stub terminal at MCC is more useful.
I think you're still latching on to this idea that it's some kind of GO service, or marginal improvement on GO service. Lakeshore is nothing like proper regional rail. Just because we don't have something now doesn't mean that it can't be done.
First we'd need to A) get all-day service on all lines, B) eliminate the double fares C) divert the Milton line to MCC through a tunnel and build a new Erindale station, D) electrify the entire GO system, E) buy new rolling stock F) add new stations. Doing any of those items would be a challenge in and of itself. I think it's far easier to just extend the subway to MCC. Probably cheaper too.
This is a lot more than all-day service on all lines. I think there's no point to doing these piecemeal improvements. We need to completely rebuild corridors, either simultaneously or sequentially, for proper regional rail. I'd do Milton first or maybe second after Lakeshore. The rebuilding process would include all of the items that you mentioned: electrification, new rolling stock, and additional stations. For Milton, it would include the diversion project. You're making these things sound impossible, but none of them are particularly difficult. Laying tracks, building a couple tunnels, building simple surface stations, and buying rail vehicles is not difficult.
I can completely understand the argument that you want a parallel subway line to serve the area between Kipling and MCC. That might make sense, though I think it would likely permanently preclude any real large-scale improvement to transit in Mississauga. What I don't understand is this LRT promoter mentality that building any large scale projects (at comparable cost) that would really dramatically improve transit across the service area is "impossible" and we have to settle with a basic, slow approach.
You're right that an MCC subway extension might be easier or at least much more familiar and easy to understand, but that's because it's far less useful! All it would serve is MCC and its immediate environs. Regional rail would serve all of Mississauga and connect neighbourhoods like Erindale and Streetsville and Meadowvale directly to MCC by rapid transit, allowing MCC to develop into a real employment centre in its own right.