Further to my suggestion of routes with historical variants ( my preference for GWR ) would be the Lickey Incline in Steam and in recent variants. One reason is that the Bromsgrove Station has been moved. Worcester to Birmingham would be the modern route and Glouster to Birmingham would be the steam version. We have this variation almost with TSW2 having the old and new Bakerloo trainsets, but with the re-work on GWR we could miss the chance at route preservation in TSW5 as may be the case with WCML as it now stands as North and South instead of Then and Now. In some routes we could have 3 choices: Steam World, Diesel World and Electric World. With multi-Terabyte SSD iit is really no longer about Gigabyte storage limits but rather imaginative simulation. Flight Simulator is a case where this might also be an opportunity missed by choosing Cloud over large local storage.
If msfs went with local storage, nobody would have the space to run it. Streaming the entirety of planet earth to an acceptable level of detail is a huge amount of data that no standard computer would have space for it anyway
The Lickey Incline is one of the steepest. Bit of a missed opportunity having it in a modern route, there's nothing like driving a steam train up a steep hill. We can do it in free roam already at least.
Even today there are occasionally some very heavy freight manifests that require a banking loco at the back to get it up the incline. I'm not sure if they've included any like this in BCC. For a then and now see the footage below:
If we ever got a steam-era route that included 'The Lickey' you couldn't do it without Big Bertha even if she was withdrawn in '56
