Hello,
I had the same problem. Going into settings, then "mail, calendar, accounts" and the ipad froze. I then tried soft and hard resets. I tried to change some iCloud settings. It wouldn't have any of them. Not accepting changes, freezing the screen. Apple support helpful but clueless. I started a full factory reset when itunes came up and said "error" we cannot restore your ipad. I went on the ipad and it worked fine, without having to reinstall anything.
Not sure yet whether this is a temporary or permanent fix.
Any more clues on why that is happening?
Volker