I second this! Would be cool to be able to open the various shipping containers we come across instead of them always being open or closed.
edit: It really would be easy to do with how containers already work. They're not singular placeable objects- they're built with blocks like most everything else. All they would need to do is add a new block for the doors that can be interacted with.
At the very least, should be fairly easy to mod in as well. (assuming you know how to create new blocks, which I sadly do not...)