Tasks have a paperclip icon to indicate there is an attachment. It would be good to have a "notes" icon as well for tasks, so you can tell at a glance whether additional notes are sitting in the task instead of having to open up the task to see whether notes exist.

If you enter a task with a due date, it should show up in your calendar as either an all-day event or an event at the time assigned (if applicable). When the task is complete, it should update in calendar with the strikethrough formatting.

We can see our tasks from One Note. Can we also have TEAMS and PLANNER tasks be linked to Tasks as well?

add "my day" function in outlook task (like outlook.com ver.)
so when we use calendar, we can also see "my day" in the sidebar

One should be able to just drag and drop tasks from the planner and from ToDo into outlook Calender, Thus you can schedule your personal working day, no matter what preference you have for a ToDo-Application.

Adding CC field in assigned tasks it is useful for person related/dependent to track task status and get notified about task status

It would help a lot to be able to set a default reminder for each recurring task in the recurrence dialog.

When task is assigned to multiple users, a feature to show who all have completed the task will help in tracking the completion

Please update outlook tasks to allow an assigned task to be recalled and updates if the scope of the project or task changes.

Be able to remove the "Response Requested' on an appiontment email after sending it.

For recurring tasks that are assigned it would make things easier if reminders for each occurence could be enabled for the assignee. This type of functionality would reduce the need for sending manual emails requesting someone to complete a task.

Allow sharing of "To-Do List". I can create a new folder and share it. The task in the new folder show up in the To-Do List folder. I would like the option to share my To-Do List folder, so that the person I am sharing my To-Do List folder can see all my task and due dates.

In order to save time it is necessary to be able to put a newly created task into a specific task folder on creation.
So when you're creating a new task you should be able to browse through available folders or create a new folder right from the task creation window. (should work similar to the category setting for a task)

Currently you have to create a task (e.g. by flagging an email message) and then you need to go to tasks and distribute newly created task into a specific folder which is not convenient and consumes additional time.

While in calendar view, when a task is dragged from the task pane to the calendar, the created calendar event is shown as "busy" by default. My idea is to have a setting were dragged tasks create "free" or "tentative" events by default.

Automatic mail trigger for task reminders before due date and on due date and Escalation mails if task not completed on due date.

provide "assign alert to recipient". This option exists in the email.
Provide "assign multiple tasks" to one recipient at a time

Some way of tracking tasks/projects when you send. rather than individual emails coming back and having to track. If you send an email or a new format of say a Task Email as they complete they can click done or something and there is a running total of who has completed it and when.