Rate you're going with the District, you might as well convert ALL the subsurface lines to 25kv operation!
Ohh, has someone been tapping into my wibble? Well, not quite:
I need to have a quick go at some of this lark. Changes I'd make:
Grade separate the Picadilly and District. Send the Picadilly to Ealing Broadway where it would burrow under, surface at West Ealing and run to terminate at Greenford.
District then goes to Uxbridge.
Bakerloo surfaces briefly at Queens park, but then goes underground again to run north west.
North London line fully four-track from Camden Road West Junction to Dalston, with Watford services running to New Cross then onto Orpington as a CrossRail route, extended under Watford Junction to run to St Albans.
All LO and Subsurface Lines converted to 25kV AC.
Al LO and Subsurface Line platforms rebuilt (at staggeringly large expense) to be 200m with Platform Edge Doors and near as possible step/gap free- obviously with full step free access to every single platform.
Crossrail 2, I'd ditch the current north end plan. Instead, I'd have it surface at Bethnal Green and Stratford. I'd give Cambridge/Stansted services separate tracks from Hackney Downs to Harlow Town. Like so: