Really feels to me that this is doubling down on the original mistake, which was to route the Sunderland terminus to South Hylton, a small peripheral village with no potential for housing or economic growth.
I can’t believe the complexity of what’s proposed for the stretch south of the Wear, with zero benefit in terms of additional stations (not there’d be many users anyway). That suggests to me it’s a sacrificial lamb when this all gets too expensive, and the intention is to end up with Leamside phase one, with an extension from Pelaw to Washington South. I think that has merits - the bus to Heworth has always been busy from Washington, and there’s a huge tract of land between Follingsby and Nissan that could be built out for industry and/or housing.
I understand the politics, but Sunderland would benefit more from an extension from Park Lane/University, up the old mineral line through Silksworth Sports Complex to Doxford Park. Doxford Park is taking a lot of the city’s housing growth and has a business park that’s reaching an age where it needs renewal. Its position at the junction of A19/A690 also enables it to act as a P&R railhead / bus interchange for folks from the coalfields and towards Durham. This was a potential extension first identified in the 70s when the original phases of Doxford Park were being built. The city’s waited a long time. A Seaham extension on National Rail lines would be another cheaper option and would bind that town into Sunderland more - that NR station is doing really well on a pretty limited Northern/Grand Central service.