I would like to see the Silver 1972 Stock from the New Journeys pack sub in on WCML south. As this train does show up on the Bakerloo line it is only fitting that is can be used on the Bakerloo section on this route, this would add a bit more variety to the route especially if it had a small chance of showing up when driven by AI.
But that is the stock in it's original, as-built condition and thus not 'accurate' for WCML: South. the 38 stock would be more accurate as a 38 stock train does run railtours on the Underground