You don't understand the issue. It is not about sharing anything via icloud OTHER than find my iphone. In ios6 you could have your own personal icloud account for everything BUT find my iphone; then also create a shared icloud account with ONLY find my iphone enabled.
This allowed families to see ALL of their ios devices from ONE single find my iphone login. Much better, particularly if you have kids with ipods that they lose behind the couch (so you could send the ping sound). Now you can't do that. I can only see my personal devices in find my iphone.
So if my wife or kids lose their iphone, I will have to find a pc and logon with their individual logon to find it.
The old way was more convenient (but I guess less secure; which is way Apple does not allow it anymore?). No one from Apple has said anything though. So it is not clear if this was intentional or not.