Western Metro city
Yes the NW Metro has mostly forced their hand which is what I indicated. The NW Metro curve left from Bangalroo, where as the Western Metro comes in curving to the right and needs to cross the NW Metro to be on the north side of NW Metro at Martin Place. I cannot see how you get at least 200m in straight and level track in this alignment. The Bangalroo area is the only place where the track is close enough to the surface to be viable before going under the elevation of Wynyard.
Western Metro to Central and BEyond
The line finishes at what Macquarie street or just beyond and the station platforms are close to if not parallel to NW Martin Place station. So of course it will point SE. However does the NW Metro continue to SE? From what I can see, it turns almost 180 degrees backt to Pitt Street. Why couldn't the Metro West follow the same, the turn wouldn't even be as tight.
When Phase 1 of NWRL Metro was being constructed, what was the level of documentation to commit to extend to the city? Lines on a map and a basic commentry about future extension. The project had no detailed engineering done south to the city, just expectation that phase 2 would do roughly XYZ, which changed in detail, which included at some point dropping Hurtsville and Liverpool. At the the time of NWRL Metro construction they didn't even know how they were going to fund the extensio, Likewise Phase 2 of Metro west is lines on a map and basic commentry unless you are in the inner circle of the govt and have more unpublished detail. With Metro West not due for completion for at least 7 years, there is no rush and/or there will be an annoucement for the election in either 2023 or 2027.
I would bet a carton that if the current govt is to be retained the extension will continue and there will be a station at Central with a SE alignment. However if there is a change of govt (likely) then who knows because we all know the first thing a new govt does is rebrand major projects to reflect their own marketting. As well why would the line continue east to follow the ESR? Yes it could follow the M1 and avoid Central or together, but whats the advantage? No one lives in Moore Park so best to go under Surry Hills. Which again woudl they go so close to Central but not be Central? Unlikely, my view.
Extension to SE La Parouse
Any map showing a $150m Metro station at La Parouse needs to be treated with a "yeah, right" attitude unless there is a serious intention to cross to Cronulla. However as the connection will require 11 km of line just to join Malabar with Cronulla I don't see this being feasible. Miranda to Kogarah achieves the same outcome, which is in the plan.
BMT via Bridge
You would only run BMT across the bridge for sectorisation or at least remove crossing paths on the Western Main as an alternative to fly overs. Personally I cannot see why it cannot be done technically as those people who fill the BMT train are already filling suburbans so I think it would all balance out, but I am not proposing it would be done.
Can you explain to us how digital signally speeds up the express services which already have few stops and assumed already operating at track speed at all times? Isn't a green light still just a green light regardless of the electronics behind it?
Westmead Station and users away from T1
The drawings on the site seem to show Westmead etro is partly under Westmead DD, the interchange would appear to be no longer than if there were two additional platforms to the south of the existing 4 track corrior. As such if already on T5 services and other non HR PT, then if the Western Metro suits you then yes it would pull people away from HR
When I says suits, this would indicate your destination is perhaps Paramatta station away from the existing station, although probably not significant, but more so other destinations further down the line including Martin Place district.
Likewise anyone access rail from Paramatta.
Will it be a white elephant, I very much doubt it. My data is old, but it shows 50,000 people a day joining at Paramatta and Westmead, I'm sure its alot higher with Martin Place being the 10th highest destination.