I have recommendation for the Train Sim World Series. If you know a bit about the game beamng.drive, you may or may not know there is an editor to where you can customize your vehicle by adding and removing parts. If we had that kind of feature in TSW, it would be a small but nice feature so that you could customize your trains to your desired look even more.
Thus is a feature that actually sounds pretty cool. If we had fictional trains that is, as rarely do trains actually have a wide range of customizable unless you count in possibly cabin changes.
Yes that is what i mean. Being able to customize the interior of most trains and maybe small exterior objects like destination displays and mirrors. I also think that it would be nice for a livery designer option where you can put paint and decals on the inside of the trains because when i like to make up my own make-believe train company it is annoying to still have the original company branding on the inside, for example, DB.