I would maybe even expand on that Idea and say that Train stations should be programmable in the way that you can say which train should be loaded/ unloaded by which freight platforms. It would be nice to reduce the amount of stations and finetune the amount of trains needed.
However I see problems with loading and unloading one freight platform at the same time, since then stuff will be mixed up and your production lines will only jam up with items you wanted to be transported off. It would be wiser then to split the container into a loading and an unloading part and then you may as well just use two freight platforms in the first place. Also I don't see how two freight cars at once could be loaded by one freight platform? That as well would be a thing already possible by connection output and input of two freight platforms.