I like the concept of this idea!
I'd like to see the tasks devided into different levels where you have to compleate a sertain number of tasks from each level, but not all of them. Each level would then contaion tasks related to each of the basic proffesions. That way you can specialice in one proffesion if you like or just pick a litle of each.
EDIT - turk1077 beat me to it
