I wouldn't write the idea off so quickly. Esp with STAR due to start, LO I would imagine to eventually extend Stratford services in the near future northbound too..
1) you’ll have to trust me here, it wont work. There’s no platforms at Liverpool St to borrow, because those being vacated aren’t long enough for trains off the main. And even if they were, you would have to line up a path off the WAML fasts at exactly the same time as both an up and a down gap on the mains, which means that these latter two have to line up perfectly with each other, and a gap on both the up and down electric. It would make the Red Arrows look uncoordinated.
2) how will LO extend services northbound?