It would be great if we could see the subtasks listed beneath the main task and be able to manipulate them in board and list view.
I am currently not using the subtask feature for exactly this reason. I have switched to using checklists for now. This feature would enable me to switch back to subtasks which is a more optimal workflow.
I think this is basically what I'm looking for as well. I was surprised when i went into board view and was unable to see subtasks outside of the main task.