My suggestions:

1. Add in the function in the doit.now column : insert the task (either a + button or integrated in the right click menu)

So that you could directly add in your task in the right place instead of finish all the detail and then drag it up and down(that is quite troublesome)

2. When you drag the task in the doitnow column, if there is a lot of tasks it will not automatically scroll up/down(even I drag the task and remain at the end of this list(shown in the screen)) like windows.

3. (Again) Please allow us to drag from low important to important directly instead of editing it inside