HIT, Week View, and Backlog by Roles on the Schedule Page
I would like to suggest moving the Backlog by Roles to the bottom of the Schedule page. When the three panels are in the same view, it is easiest to apply your philosophy: drag items to HIT and from the to the weekly schedule. Currently, I often forget about the backlog and I do not go to drag items to HIT. Sometimes I enter the same item twice (in the backlog and forget about it and then again, straight in the Plan of the Week, when it emerges again, this time with more urgency rather than having had planned it.)
We are not going to bring all panels in one view simply because it makes the whole user interface very busy and overwhelming.
We prefer to keep each section separate.