Proposal: Filtering by Multiple Tags
At present, the task list can be filtered to display all tasks with a single given tag by selecting appropriately in the tag sidebar.
While useful, this is very limited and not terribly helpful for bringing key tasks to your attention according to you present circumstances (e.g., at work, with fifteen minutes available).
Filtering by multiple tags would allow for contexts and resources to be used as tags and then a small and specific set of relevant tasks would be available for your attention when you filtered by the specific details of your present circumstances.
For example, if you use tags to identify priorities, probable durations, and contexts for a given task you can quickly select @1, @10m, @email to identify those high-priority emails you need to send that will likely take less than 10 minutes. Add a @personal or @work depending on where you are, then the list of tasks could become more specific still, enabling you to focus very specifically on something that you can achieve immediately given where you are and what's available at that moment.