It would be great if the gradient were separate from the speedometer in the HUD. So we can remove the speedometer but still have the gradient.
Not just gradient. The whole HUD could use with a lot more customization options. The speedometer is huge, but it contains some useful info, for example I quite like the door status icon, the throttle lock indication and the current speed limit displayed on the speedometer, but I don't necessarily need the current speed (as trains usually have their own speedometers) and it certainly could all be a lot more compact.
Still think MSTS did it best with the little boxes that could be opened and closed or discreetly moved to the least obtrusive location. I would also like to see the scenario marker, aka the lollipop reworked, as this almost invariably obscures gantry mounted signals.
Oh I turned those annoying lollipops off. I do wish there was an option that enables them only for on-foot objectives and in-cab control objectives. But for all "go via" or "stop at" objectives one can rely on the HUD instead of the annoying lollipop.
I would like the Hud to be like the one on Train simulator were it runs along the bottom of the screen