Open Radar

 
I usually always want all my Macs and iOS devices to have subscriptions to the same set of external calendars, but that set changes over time... managing this per device is very, very cumbersome and so the set is always out of sync on some device.

Why not simply offering this: I log in to icloud.com, I create a new calendar there and then I can choose that this calendar is to be synced with an external calendar (ICNS file via HTTP), so that all I have to do is enable iCloud on all devices and I will have access to that calendar. Either you just pass through the external calendar (you don't store anything for that calendar but the URL and every time someone requests that calendar, you pull the ICNS from the external soucer and deliver it) or you cache the data for the case the external source goes offline (in that case you store the events locally and just at regular intervals sync the calendar with the external source).