Any west to east layout for the HS2 would need to be to the south of the station, not the north.
The width of the car park isn't sufficient for the number of platforms that were planned, and the area is also need for platforms to accommodate future TRU/NPR growth. You'd also be putting a massive structure
As mentioned, that curve is far too tight, plus it crosses over an already congested series of junctions. At least part of that area would be built over the dark arches so hugely significant strengthening works would be needed. Parts of the dark arches and that area are used by the adjacent hotel, and the NR owned arches are ripe for commercialisation and improved entrance and egress from the station.
The area is also the main pick up and drop off for the station (and is already subpar and needs replacing), building more track onto there simply exacerbates the issue.
Interestingly the
David Higgins report on HS2 station options for Leeds had an option for a station on the E-W axis to the south of the station, but with trains approaching from the east rather than the west, I assume for the reasons mentioned above - one of the drawbacks mentioned for this is the difficultly in approaching from the east as it impacts alot of heritage assets in the city plus employment land to the east. And any E-W aligned station would preclude any further expansion of the station for existing services in the future.
A t-shaped station, although preventing through services for HS2, would mean a more straightforward approach, provide better integration for the station into the city (Leeds station is very constrained due to it's location) and would not compromise the existing entrances and their capacity.