Possibility to create boards based on fields (status, tags, folders, context, assignee,...) and display your tasks with custom fields (you can select which fields of the tasks to see) then you can rearange in drag & drop and get to the detail of each task. Basically a bit the way you do in Kanban. GTD is great but when you need to reorganize your tasks or give a visibility to the team a kanban way view is just what you need. Basically all the features are there already but not visual and you have to change the value of the fields with the drop downs.