Mercy yes! Especially in the Daily Targets List. My DT list can get to be enormous simply because the project I'm working on that day can have so many steps in it. If I had the option to collapse those tasks into one project title on my Daily Targets List is would do amazing things to clear my head and keep the entire arc of my day in my awareness.

Also with a huge daily targets list it's hard to keep everything in perspective. It's important to remember what goal we are supporting by doing each task. Sub-tasks would keep that connection in the forefront of our awareness.

This would help simplify the Lists field by being able to check off sub parts of a task. Most projects have multiple tasks with many sub-tasks of each. This would make the new Lists extremely powerful.