I conversely think that it is good to spread the interchanges on the route to not overload any single place and to placemake some outer focal minor ‘hubs’ (ie somewhere with two lines!)
Neasden has a ton of housing potential, much as has been done at Wembley. But you wouldn’t call Met services there. Harlesden might see the same.
And as for West Hampstead - in another lifetime yes ideal but not remotely possible in the footprint today. But Finchley Road is already a major focal point and interchange (esp w buses, coaches) and bridges into Hampstead, Frognal etc - quite a wide catchment)