Unfortunately dragging isn't available for mods but clicking to expand the task makes a lot of sense to me.
I'm not sure how much work it will be but eventually I do want to add a status to each task (I found playing it in multiplayer this matters a lot more), and if there's a status then it makes it more confusing to have a checkbox as well. What do you think of this layout and icons?
image
At the left the checkbox would be replaced with a dropdown button for task status, and then clicking the task title would expand/collapse the task details and subtasks.
I do really like the separating checkbox and task title idea, so if this seems like it might be a bit difficult to implement now I might just do that and add the status later. Just wanted to hear what you both thought about the task status idea.