Daily Plan is nice, but I would much rather be able to put an estimated time on every single task. That way I can sort and select tasks at any given moment based on the amount of time I have to work in that specific moment, which is what GTD is all about. Estimating the time a task should take place prior to selecting the task(s) you're going to do, because estimated time for a task is something that needs to be considered when selecting the task. The way you have it set up now doesn't maximize the potential/usefulness of an "estimated time" feature.