I feel sorry for your experience but the primary reason is that Train Fever is based on Transport Tycoon/OTTD than Railroad Tycoon (the 2 games are fundamentally different). It’s a shame that you can only build level crossing by laying railroad over exiting road, but not the opposite. I just don’t get where that “upgrade with restaurant, or cargo storage, or waiting rooms” complaint comes from. If these options of expanding the station come from Railroad Tycoon, mod is the only thing could grant your wish, which isn’t a deal breaker IMO.
I agree the game is incomplete and there is room to improve, but I don’t regret paying for this game and I enjoy the game despite its obvious flaws. I just hope if someday the original developers decide to stop updating the game, they could release the source code so the volunteers can improve the core gameplay like the OTTD community does.