Task in Focus
One of the main topics of Getting Things Done is to focus on one task at a time. It'd be nice for Todoist also to provide a "Task in Focus" view or feature that will help me focus on one task, getting it done and then go back to my task list. This may be achieved by having an item above the "Today" item in the left nav and calling it "Now" or "Focus".
Lots of apps enable you to do that, but I've been using the Swipes App that does this well.