While accuracy would be reduced, there would be less drain on the battery. Currently, the GPS can be turned off in the system settings but this would be more convenient.
It would also get rid of the issue on some devices in which the GPS stays on even when all location alarms are canceled.

The app can currently display tasks in the order that they appear in Google Tasks, but this order cannot be changed from within the app.

One trick to implementing this is that each view can display tasks from different folders, contexts, and even different accounts. So, the order of tasks in one view cannot be applied to another view, because the tasks being shown are different.

This could allow start and due dates to be set automatically based on the status of another task.

Here's another possible implementation: Use the status field. A task can be set up so that its status switches to "Next Action" after a specified task is marked as complete.

Make sure to include many options for template start and due dates, such as "today", "tomorrow", in 6 days, in 1 week, in 2 months, etc.

Now, when I press the new task icon, I get a popup to enter the title of the task but first I need to touch the input field for the keyboard to appear (= one unnecessary click every time).

Great software in terms of functions, but it lacks usability. What about simple and clean interface like in RTM or Astrid? You can organize main screen to be more comfortable with icons instead of text lines. Make design more delicate, rounded corners are ugly. It should have professional look, it is paid app, not a student home project! I would pay 20$ for this app if it will have clean interface.

Examples: Today, tomorrow, Monday, one week from today

This would only be applicable if subtasks are being indented

Ideally, this could be combined with the mult-select feature to e-mail multiple tasks.
Also, provide an option to e-mail the task in Toodledo's format. This would allow someone to assign a task to someone else simply through e-mail.

Assign a widget to one of the built-in views or a custom one. This eliminates the need to re-enter all of the filter, sort, and display settings if a widget has to be deleted and re-created.

This would provide the ability to select a tag, folder, context, goal, or location and include all tasks that do not contain it.

It is possible to set this up so that it can be done from anywhere in Android.

Perhaps with the ability for users to define their own colors.

I believe a way to utilize Evernote would make Ultimate To-Do List a true one stop shop for organization and referencing.

This would mean, for instance, that a task that could be completed at either home or work would appear on both lists. Which would save the effort of moving it from one to the other.

This would prevent the title from being cut-off in the list of tasks.

Consider allowing the user to choose a value that is relative to the due date (for example, 1 day before).
This would include both the reminder date (relative to due date), and reminder time.