Task due date should be automatically added onto Outlook Calendar
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.
This is something Google implemented that works wonderfully. You should also be able to turn off "task view" if your calendar is becoming too cluttered. But many people - myself included - basically live by our calendars and if the task doesn't show up there I won't remember it.
Miles Gentry commented
Do not support this idea. Too much detail in a calendar. Clutter.