So if you are on snow leopard and mobile me; and don't want Lion on your machine- but you just bought a 4s (with ios5)....
Your back to pluging in your device to itunes to manually manage you contacts and calendar that worked perfect in the ecosystem of syncing in the MM cloud yesterday.
Mobile Me still works with iOS 5 (I ran it for awhile) and the service will run until next year. Plenty of time to come up with a solution if you ask me.
The same reason Outlook on the PC and Mac separate tasks and calendars - they are intended to be be different things.So why did they not just add the reminders to the calendar app?