large all-in-one train station

Train station in the game now is too inflexible and place them also required tedious line management.
What I suggest is make train station like train depot and ore-sorter the train station can connect to train rail like train depot and it's I/O is like large ore-sorter, you can load/unload cargo in single station. And you can extend the train station's length and width by adding something like Train Depot Extension to make it have higher throughput and trains capacity.
By this design, you can change station's demand and supply any way you like without change station module like now. And I think you can make some algorithm to make cargo transport between station easier which eliminate line management a lot.

It would be strange to have building that would just "magically make things happen" inside, current state is more flexible, modular, logical and you actually see how it works and wagons gets loaded/unloaded. Also you can have much longer trains than is the station length.

I'm thinking more like a loading dock and unloading dock that can handle like 2-4 rss at a time. loading and off loading respectfully like it is now.

The reason why I want this kind of station is because the ordering of train station modules and train wagons are highly coupling.
It is hard when you want to have fluid/loose/unit mix type or different kind of cargo of same type to transport.
What I suggest is have some "universal" load/unload which means you can load/unload any kind of cargo in same place without matching it's type but you still need corresponding type for I/O though.
For example, if you want to transport from iron mine now you will at least build 1 iron station,1dirt station ,1 rock station, 1 fuel station for mine and each of them for where you want to transport to, that's 8 stations! And manage line for each of them! and each line will have at least 1 train no matter throughput.
But for large all-in-one station it only need 2 station and 2 train (assume 1 for loose 1 for fluid), line management? Maybe not needed (depends on how to implement, let's say you can assign train to station like storage).

And for "magically make things happen inside" part, I didn't mean whole train goes in and magically whole train goes out, you can still see batching and how things happening like now, only difference is train didn't need to match module like now.

A pre-build cargo train station sounds really good. Something like 2 of each type of cargo + ability to add a maintenance module. On big maps this will be a QoL welcome change.

I actually wouldn't mind the concept of a route pool and being able to assign the trains to a pool. So I could have a route pool of loose goods, so a train might be hauling dirt one load and stone the next. That way I can still be explicit about what goes where and lines and things, but for less frequently traveled routes, I don't have to have a train just sitting idle.