Add field for Complexity/Effort

There are three main factors to planning/managing workload - how urgent is it (you already have a due date), how important is it (you already have a priority) and how easy/difficult is it to achieve (I suggest adding a nice simple high/medium/low complexity field). You should then be able to sort the lists by all these different factors. This gives a much better picture of how much work is actually involved in any task list.