Go ahead erase my Angry Birds apps.
Why would anybody keep important data on their iPhones without backing them up?
Now, if they hacked dropbox, I'd have a problem.
Well, do you have a Mac, and only Macs?
If so, AppleID becomes a gateway to access and lock everything, at the same time. Presumably it isn't too far before they can remote control your computer as well... which is authorized via AppleID as well.
Apple had better get moving on significant security improvements in the system, or Really Bad Things could happen.