Willesden Junction - could an extra crossover or bidirectional signalling help?

More of a prototype question than a sim question, but is there a reason all trains from Kensal Green Junction approach Willesden Junction via the down line? For trains towards platform 3 it makes sense, but for trains to platform 2 why not permit use of either line at the signaller's discretion, depending on whether there is something approaching from Kensal Green or from Harlesden? That would allow parallel moves and fewer delays in general. If trains are expected to cross between Willseden Junction and Kensal Green Junction, then a facing crossover or slip in the diamond could permit that.

It would be unusual to put in that kind of reversible working even within a box area unless there was a proven, regular traffic need for it. I can think of a huge number of moves that would have provided extra flexibility for the boxes I signed, but which were never provided - the working round the pinch points was never so much of a problem as to make it worth the expenditure. The bobby just had to be on top of what had priority for regulating purposes and ready to move quickly when trains passed to minimise delays.