The WLL feeds into, and ostensibly is, the NLL route - in passenger terms. More seamlessly than onto the WCML!There's little sense in the WLL being connected to the NLL anyway. The TFL journey planner typically sends journeys from the NLL to the WLL via other routes because Willesden Junction is such a circuitous route. For instance if you ask it for Camden Road to Shepherds Bush, it might tell you to ride a train which has COME FROM Shepherds Bush to Highbury & Islington, and then get the tube to Shepherds Bush!
The entire 8tph NLL service should go to South Acton, from where half should go to Richmond and half should go (over newly electrified track) to Hounslow. The people of Hounslow would much rather have this than have the West London Orbital service to Brent Cross.
Can 4tph WLL go to Watford / St Albans Abbey, via new platforms on the Relief Lines at Willesden Junction?
If anything, the Richmond route could naturally flow towards Dudding, but it's not even wired or passenger specced. And without the OOC station, you are sending people to nowhere.
Also both routes give Willesden-Stratford high frequency, which is now needed - sometimes up to 10tph, better than many tube branches and always busy.